Calcium-binding proteins as allergens

Abstract

Calcium-binding proteins, particularly those in the EF-hand family, are found ubiquitously in nature, primarily for calcium transport and storage in the body. In this review, we discuss allergens in the parvalbumin, polcalcin, sarcoplasmic calcium-binding protein, and troponin C families, as well as additional allergens. Allergens from these protein families display a wide range of IgE reactivity and cross-reactivity. They are implicated in both inhaled and food allergies, and, due to their common presence, they are difficult to avoid.

1 Introduction

Calcium is essential for all areas of life, including muscle contraction, blood cell synthesis and function, and nerve conduction. In eukaryotes, the primary calcium-binding protein family is the EF-hand family, which is characterized by the EF-hand, a helix-loop-helix motif composed of 29–30 amino acids (1). The EF-hand motif is featured heavily in cellular signaling as it facilitates calcium movement (2). However, the specific function of each protein family will vary based on the structure, expression pattern, and cellular location of the protein. The EF-hand superfamily is particularly diverse since some proteins are composed solely of the EF motif while other proteins have the motif joined to the rest of the protein (1).

Many protein families in the EF-hand superfamily contain allergens (Table 1). Included in these families are parvalbumins (PV), polcalcins, sarcoplasmic calcium-binding proteins (SCPs), and troponin C (TnC). All of these protein families contain important allergens that cause significant reactions in individuals allergic to various organisms, including seafood, pollen, and mites (3). Two additional protein families, psoriasin (S100A7) and mitochondrial calcium-binding protein, each contain one registered allergen that have not been studied in depth.

In this review, we discuss the function, structure, and immunological features of proteins from these families. Notably, we focus on the immunological impact of calcium-binding on these selected allergens and the allergens’ IgE cross-reactivity. Their stability and cross-reactivity make them highly potent allergens that should be carefully studied and avoided by allergic individuals.

2 Calcium-binding allergens

2.1 Parvalbumin

Parvalbumin (PV) is considered a prototypic EF-hand calcium-binding protein (4). PV is primarily found in the muscle tissue of mammals and marine organisms as well as in neural tissue, although its exact function is unclear (5). PVs (11–13 kDa) have three EF-hand motifs, two of which bind calcium cations (Figure 1A); the AB hand has a two-residue deletion that prevents calcium binding (6). Recombinant PV is stable in high temperatures, and natural PV tends to survive cooking processes. PV is prone to unfolding and aggregating at acidic pH levels, which is consistent with reduced calcium coordination under acidic conditions (7–9).

Figure 1

PVs are categorized as either alpha-PV (α-PV) or beta-PV (β-PV) based primarily on the protein sequence and their sizes (10). β-PV is well-known as a major vertebrate seafood allergen, with 70%–100% of vertebrate seafood-allergic individuals having reactions, and has been studied in Atlantic cod (Gad m 1), carp (Cyp c 1), salmon (Sal s 1), and saltwater crocodile (Cro p 1), among other organisms (11–15). Bony fish have both α-PV and β-PV, while cartilaginous fish have only α-PV. Interestingly, β-PVs are highly cross-reactive with each other (average sequence identity of 70% across registered allergens) but not usually with α-PVs; this is likely caused by the lower sequence identity (approximately 50%) between the two isoforms (16). α-PVs are also rarely classified as allergens due to low IgE reactivity (14). The calcium binding residues on the EF-hands are highly conserved (Figure 1B), making the lack of cross-reactivity and varied IgE binding between the two isoforms more interesting (10). Individuals with seafood allergies to bony fish will likely have significant reactions to β-PV, including allergic responses caused by protein cross-reactivity.

PV has been extensively structurally characterized with both x-ray crystallography and NMR. Molecular evaluation of PV has shown extreme structural conservation among the protein family. All x-ray structures of wild-type PV have two metal cations bound, demonstrating the proteins’ reliance on metal cations for stability. Some x-ray structures have been determined for mutant PV, with residues in the CD or EF motif mutated to prevent calcium binding (4), and some NMR structures have been solved for apo wild-type PV (17, 18). Calcium-depleted PV (Cyp c 1 mutant) has been proposed as a hypoallergen for treatment of carp allergy, with an average of 1,000-fold allergenic activity lost in the mutant (19, 20).

2.2 Polcalcin

Polcalcins are found in grass, weed, and tree pollen and are considered minor allergens. The primary functions of polcalcin are signaling between plant cells and pollen tube growth via calcium transport (21, 22). There are two categories for polcalcins, two EF-hand proteins and four EF-hand proteins, with one of each having been identified for some plants. For example, ragweed has both Amb a 9 (two EF-hands) and Amb a 10 (four EF-hands), and silver birch has Bet v 3 (two EF-hands) and Bet v 4 (four EF-hands) (23). The two-EF hand polcalcins are approximately 9 kDa, while the four EF-hand polcalcins are up to 17 kDa. Polcalcins have highly conserved sequences, particularly in the calcium binding residues and are particularly cross-reactive (3, 24).

Structural characterization of polcalcin has shown that calcium coordination will significantly affect the folding of the protein. Structural variation was revealed by NMR structures of Phl p 7 (timothy grass) in the apo form or when bound to one or two calcium cations (22). Interestingly, two structures of domain-swapped polcalcin were solved, one of Phl p 7 and one of Che a 3 (lamb's quarters). These structures may be the result of the acidic crystallization condition (pH 3.3–3.4), rather than representing the physiological polcalcin, thus demonstrating the effect of calcium coordination and movement on the protein structure (25, 26).

Based on the structures of polcalcin with and without calcium, it can be assumed that apo polcalcin will have a significantly different shape in solution as compared to holo polcalcin, leading to varied IgE interaction from each protein. This was shown with Ole e 3 (olive), where the addition of calcium did not affect IgE binding, but the addition of a chelating agent lowered IgE binding by 32% (27). It was also demonstrated that calcium removal decreased the affinity of a specific human IgE to Phl p 7 over 10,000-fold (28). The structure of Phl p 7 bound to the antibody was the first structure of a specific antibody bound to a calcium-binding allergen (Figure 1C). Additionally, a version of Phl p 7 was generated as a potential hypoallergen, with two residues in each calcium binding site mutated to alanine to prevent calcium binding (29). The authors also demonstrated that calcium-depleted wild-type Phl p 7 and mutant Phl p 7 had similar structures and α-helical content to the wild-type Phl p 7, suggesting that the secondary structure of polcalcin may not be reliant on calcium binding.

2.3 Sarcoplasmic calcium-binding protein

Sarcoplasmic calcium-binding proteins (SCPs) are widely present in crustaceans, mollusks, and insects. With three EF-hand motifs that bind three calcium cations per protein molecule, they play a role in muscle calcium regulation (30–32). Their molecular architecture imparts thermal stability, maintaining allergenicity even after food processing (30, 32). Some SCPs, such as Lit v 4 (white shrimp), retain the ability to trigger mast cell and basophil activation at temperatures up to 80°C, and its structural retention after heating was shown with Circular Dichroism spectroscopy (30, 33).

Lit v 4, Por t 4 (Gazami crab), and Scy p 4 (mud crab) are major allergens, eliciting IgE responses in 30%–60% of shellfish-allergic individuals, particularly among children (33–36). Pon l 4 (narrow-clawed crayfish) and Cra a 4 (Portuguese oyster) are also considered important food allergens (31, 37, 38). Minor SCP allergens such as Cra c 4 (North Sea shrimp) and Pen m 4 (black tiger shrimp) have sensitization rates of 10%–15% in European shrimp-allergic patients, but these rates can reach over 50% in some populations (37, 39, 40). Investigation of SCP sensitization in unique populations has suggested that SCPs contribute to broader patterns of shellfish allergy and occasionally cause severe symptoms independently of sensitization to tropomyosin or another major allergen (39). Interestingly, SCPs can also act as inhalant allergens via occupational exposure. Shellfish SCPs can provoke symptoms such as asthma and dermatitis in processing workers, while respiratory and cutaneous reactions result from airborne or contact exposure, not ingestion alone (41).

The structure of Scy p 4 was determined, allowing for evaluation of IgE binding epitopes and confirming the calcium-binding sites (Figure 1D). Site-directed mutagenesis or deletions at key calcium-binding residues resulted in a significant reduction or loss of allergenicity (42, 43). SCPs from different species share high structural homology, which lends itself to IgE cross-reactivity (43). Cross-species sequence analysis (Figure 1E) and epitope mapping have demonstrated significant overlap, especially between shrimp, crab, and crayfish SCPs, explaining the frequency of allergic reactions spanning multiple shellfish groups (31, 44). SCP-specific IgE rarely cross-reacts with non-crustacean SCPs, but strong reactivity is seen among crustacean SCPs due to conserved epitopes (31, 44, 45).

2.4 Troponin C

Troponin C (TnC) is a calcium-binding subunit of the troponin complex, a multiunit protein complex essential for skeletal and cardiac muscle contraction (46–49). Structurally, TnC is a dumbbell-shaped globular protein formed largely by α-helices. The two globular domains, each with two EF-hand motifs, are at the N- and C-terminals and are connected by a long flexible linker (50). TnC in vertebrates and invertebrates exhibit some diversity in their calcium-binding EF-hand motifs and overall primary structure, although their structure-function relationship is conserved (51). In vertebrate TnC, the four EF-hands each have varying affinity for calcium or magnesium cations (52). In invertebrates, the functional calcium binding sites are more diversified (53). For example, crustacean and nematode TnCs bind two calcium cations, molluscan TnCs binds one calcium cation, and TnCs from cockroach and storage mite are each predicted to bind two calcium cations (53–55).

TnC has been identified as a minor allergen in several invertebrates, including mites, cockroaches, and crustaceans such, as shellfish (45). IgE against Pen m 6 (Indian black tiger shrimp) has been observed among 47.1% and 50.0% of shrimp-allergic populations from Hong Kong and Thailand respectively (56). Similarly, studies have shown binding among 29% of sera to Cra c 6 (North Sea shrimp) and IgE binding from 24% of patients to Hom a 6 (American lobster) (57, 58). Bla g 6 (cockroach), Tyr p 24 (storage mite), and Der p 39 (house dust mite) are minor inhalant allergens with positive IgE testing in 16.7%, 10.6%, and 5.3% of studied populations, respectively (54, 55, 59).

Currently, there are no experimental structures of TnC allergens available in the Protein Data Bank for any invertebrate TnC proteins (60). TnC can undergo conformational changes upon calcium binding, which may conceal or reveal IgE binding epitopes; this was observed with Tyr p 24, where the addition of calcium increased IgE binding (55). A conformational epitope for Der p 39 has been demonstrated in the C-terminal of the protein (59). TnC is also a heat-stable allergen, with IgG binding capacity retained at 100°C for the TnC from Scylla paramamosai (56).

Allergic cross-reactivity has been predicted for Per a 6 and Bla g 6 (54). Tyr p 24 shares 63%–86% sequence homology with TnCs from different arthropods, which may lead to IgE cross-reactivity (55). Sequence diversity, mostly in calcium binding sites, have been found across TnCs in some species and even across isoforms of same species. The three isoforms of Bla g 6, which share 68%–91% sequence identity, exhibited a similar IgE response, suggesting that major IgE epitopes are mostly in the identical regions of the protein (54).

2.5 Psoriasin (S100 calcium-binding protein A7)

Psoriasin is an S100 calcium-binding protein (S100A7). It is expressed in the cytoplasm of epithelial cells and contains two EF-hand motifs, binding one calcium molecule per protein molecule (61). It is expressed as a homodimer and has a molecular weight of 11.4 kDa (62). Psoriasin has intracellular and extracellular functions, including cell proliferation, differentiation, apoptosis, calcium transduction, and energy metabolism (63). Psoriasin expression is influenced by inflammatory stimuli and oxidative stress via reactive oxygen species and hypoxia, and increased levels of psoriasin have been associated with chronic inflammatory conditions, such as atopic dermatitis and psoriasis (63, 64).

Bos d 3 is a psoriasin allergen from cow dander with 64% sequence identity with human psoriasin. Little research has been conducted into the allergenicity of Bos d 3 independently of its homology to human psoriasin (61, 65). However, it may be an antimicrobial agent in cow's milk (65, 66). It is suggested that, like human psoriasin, Bos d 3 binds zinc with conserved histidine residues that bridge the dimer (61). Further investigation is needed to evaluate the potential cross-reactivity of Bos d 3 with human psoriasin, as well as with other mammalian homologues.

2.6 Mitochondrial calcium-binding protein

Hom s 4 is an autoantigen allergen involved in atopic dermatitis (67). It is classified as a mitochondrial calcium-binding protein, with a molecular weight of 54 kDa, and it contains two EF-hand motifs separated by an α-helical domain (67, 68). Hom s 4 is ubiquitously present, located in the mitochondria of epithelial cells, especially keratinocytes (67). It induces Th1-mediated autoreactivity via IFN-γ release (68). Some research suggests that this autoreactivity arises from the epitope sequence of Hom s 4 binding to HLA-DRB1 (67). It has been shown that individuals with atopic dermatitis that had IgE reactivity to Hom s 4 (43% of a tested population) were more likely to have reactions to other allergens, including drugs, pollen, mites, fungi, foods, and animals (69).

3 Discussion

In this work, we have discussed allergens from six protein families that contain calcium binding domains, all of which are the EF-hand motif. PVs, polcalcins, SCPs, and TnCs, the allergens have a wide range of IgE reactivity, allergic cross-reactivity, and structural response to calcium coordination. Significantly less research has been performed into allergens from the psoriasin and mitochondrial calcium-binding protein families, but they are interesting cases in the effect of human calcium binding proteins on allergy.

Additional allergens have been suggested or shown to bind calcium, but the relevance of the calcium binding in IgE response to the allergen has not been confirmed. The allergens also do not contain the EF-hand motif expected of calcium binding allergens. Major house dust mite allergens Der f 1 and Der p 1 are homologous cysteine proteases (70). Structurally, Der f 1 and Der p 1 exhibit a papain-like fold with two domains that form the catalytic site for the protease activity (71). The structure of Der p 1 (PDB: 3F5V) also reveals a calcium cation bound distant from the catalytic site (71). While the function of calcium in Der f 1 or Der p 1 is not clear, it may play a role in ligand binding and have an indirect effect on catalytic activity (70). Three putative calcium binding sites have also been reported for major cat allergen Fel d 1 as shown in the published structure of Fel d 1 (PDB: 2EJN) (72). However, molecular dynamics studies have suggested that there is only one physiological calcium binding site in Fel d 1, which may have a role in stability of the tetrameric assembly of the protein (73).

A commonality between the allergens discussed in this work is their stability. PVs, SCPs, and TnCs retain their structure and IgE-binding capacity at high temperatures, leading to the possibility or likelihood that the proteins will survive food processing. However, most calcium-binding proteins do not retain their folds in conditions with low pHs (more acidic than pH 3). It is possible that they will refold when exposed to more basic conditions. Such refolding was shown to be possible in the case of non-specific lipid transfer protein Cor a 8 (74). Another possibility is that the aggregates formed upon protein unfolding will have different IgE-binding epitopes that still cause an allergic reaction. Thus, reactions to any of these proteins cannot be discounted, even when the food is cooked.

Additionally, most of the proteins discussed in this work display significant IgE-mediated cross-reactivity. For example, it was previously demonstrated that seafood-allergic individuals may have reactions to reptile PVs (10). Similarly, individuals with house dust mite allergy caused by sensitization to TnC may have oral allergy syndrome-like symptoms to seafood (55). The allergens from each family exhibit up to 80% sequence identity with other members of the protein family, which strongly suggests that cross-reactivity is likely. Additionally, the residues generating the calcium-binding sites within the EF-hands are often similar, leading to specific cross-reactivity on the EF-hand motifs. Thus, calcium-binding allergens in the EF-hand family are particularly prone to causing IgE-mediated cross-reactivity, making them particularly troublesome allergens.

In summary, calcium-binding allergens from the EF-hand family, including parvalbumins, polcalcins, sarcoplasmic calcium-binding proteins, and troponin C pose a significant threat to individuals with seafood, pollen, and mite allergies. They are generally thermally stable and may generate IgE-mediated cross-reactivity. Additionally, psoriasins and mitochondrial calcium-binding proteins may cause allergic reactions, possibly caused by cross-reactivity with human counterparts. Overall, individuals with reactions to one protein from these families should carefully consider other potential allergens, since additional reactions are likely to occur upon contact.

References

• 1.

  Kawasaki H Kretsinger RH . Structural and functional diversity of EF-hand proteins: evolutionary perspectives. Protein Sci. (2017) 26:10. 10.1002/pro.3233

  • CrossRef
  • Google Scholar

• 2.

  Gifford JL Walsh MP Vogel HJ . Structures and metal-ion-binding properties of the Ca2+-binding helix-loop-helix EF-hand motifs. Biochem J. (2007) 405:2. 10.1042/BJ20070255

  • CrossRef
  • Google Scholar

• 3.

  Wopfner N Dissertori O Ferreira F Lackner P . Calcium-binding proteins and their role in allergic diseases. Immunol Allergy Clin North Am. (2007) 27:1. 10.1016/j.iac.2006.10.003

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 4.

  Cates MS Berry MB Ho EL Li Q Potter JD Phillips GN . Metal-ion affinity and specificity in EF-hand proteins: coordination geometry and domain plasticity in parvalbumin. Structure. (1999) 7:10. 10.1016/s0969-2126(00)80060-x

  • CrossRef
  • Google Scholar

• 5.

  Permyakov EA Uversky VN . What is parvalbumin for?Biomolecules. (2022) 12:5. 10.3390/biom12050656

  • CrossRef
  • Google Scholar

• 6.

  Henzl MT Agah S Larson JD . Characterization of the metal ion-binding domains from rat alpha- and beta-parvalbumins. Biochemistry. (2003) 42:12. 10.1021/bi027060x

  • CrossRef
  • Google Scholar

• 7.

  Permyakov SE Bakunts AG Denesyuk AI Knyazeva EL Uversky VN Permyakov EA . Apo-parvalbumin as an intrinsically disordered protein. Proteins. (2008) 72:3. 10.1002/prot.21974

  • CrossRef
  • Google Scholar

• 8.

  Permyakov SE Bakunts AG Permyakova ME Denesyuk AI Uversky VN Permyakov EA . Metal-controlled interdomain cooperativity in parvalbumins. Cell Calcium. (2009) 46:3. 10.1016/j.ceca.2009.07.001

  • CrossRef
  • Google Scholar

• 9.

  Taki AC Ruethers T Nugraha R Karnaneedi S Williamson NA Nie S et al Thermostable allergens in canned fish: evaluating risks for fish allergy. Allergy. (2023) 78:12. 10.1111/all.15864

  • CrossRef
  • Google Scholar

• 10.

  O'Malley A Ray JM Kitlas P Ruethers T Kapingidza AB Cierpicki T et al Comparative studies of seafood and reptile α- and β-parvalbumins. Protein Sci. (2024) 33:12. 10.1002/pro.5226

  • CrossRef
  • Google Scholar

• 11.

  Swoboda I Bugajska-Schretter A Linhart B Verdino P Keller W Schulmeister U et al A recombinant hypoallergenic parvalbumin mutant for immunotherapy of IgE-mediated fish allergy. J Immunol. (2007) 178:10. 10.4049/jimmunol.178.10.6290

  • CrossRef
  • Google Scholar

• 12.

  Perez-Gordo M Lin J Bardina L Pastor-Vargas C Cases B Vivanco F et al Epitope mapping of Atlantic salmon major allergen by peptide microarray immunoassay. Int Arch Allergy Immunol. (2012) 157:1. 10.1159/000324677

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 13.

  Moraes AH Ackerbauer D Kostadinova M Bublin M Ferreira F Almeida FC et al 1H, 13c and 1⁵N resonance assignments and second structure information of gad m 1: a β-parvalbumin allergen from Atlantic cod (gadus morhua). Biomol NMR Assign. (2013) 7:2. 10.1007/s12104-012-9393-y

  • CrossRef
  • Google Scholar

• 14.

  Ruethers T Taki AC Johnston EB Nugraha R Le TTK Kalic T et al Seafood allergy: a comprehensive review of fish and shellfish allergens. Mol Immunol. (2018) 100:28–57. 10.1016/j.molimm.2018.04.008

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 15.

  Ruethers T Nugraha R Taki AC O'Malley A Karnaneedi S Zhang S et al The first reptilian allergen and major allergen for fish-allergic patients: crocodile β-parvalbumin. Pediatr Allergy Immunol. (2022) 33:5. 10.1111/pai.13781

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 16.

  Kuehn A Swoboda I Arumugam K Hilger C Hentges F . Fish allergens at a glance: variable allergenicity of parvalbumins, the major fish allergens. Front Immunol. (2014) 5:179. 10.3389/fimmu.2014.00179

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 17.

  Henzl MT Tanner JJ . Solution structure of Ca2+-free rat beta-parvalbumin (oncomodulin). Protein Sci. (2007) 16:9. 10.1110/ps.072837307

  • CrossRef
  • Google Scholar

• 18.

  Schuermann JP Tan A Tanner JJ Henzl MT . Structure of avian thymic hormone, a high-affinity avian beta-parvalbumin, in the Ca2+-free and Ca2+-bound states. J Mol Biol. (2010) 397:4. 10.1016/j.jmb.2010.02.014

  • CrossRef
  • Google Scholar

• 19.

  Swoboda I Balic N Klug C Focke M Weber M Spitzauer S et al A general strategy for the generation of hypoallergenic molecules for the immunotherapy of fish allergy. J Allergy Clin Immunol. (2013) 132(4):979–81.e1. 10.1016/j.jaci.2013.04.027

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 20.

  Zuidmeer-Jongejan L Huber H Swoboda I Rigby N Versteeg SA Jensen BM et al Development of a hypoallergenic recombinant parvalbumin for first-in-man subcutaneous immunotherapy of fish allergy. Int Arch Allergy Immunol. (2015) 166:1. 10.1159/000371657

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 21.

  Okada T Zhang Z Russell SD Toriyama K . Localization of the ca(2+)-binding protein, bra r 1, in anthers and pollen tubes. Plant Cell Physiol. (1999) 40:12. 10.1093/oxfordjournals.pcp.a029512

  • CrossRef
  • Google Scholar

• 22.

  Henzl MT Sirianni AG Wycoff WG Tan A Tanner JJ . Solution structures of polcalcin phl p 7 in three ligation states: apo-, hemi-Mg2+-bound, and fully Ca2+-bound. Proteins. (2013) 81:2. 10.1002/prot.24186

  • CrossRef
  • Google Scholar

• 23.

  Pomés A Davies JM Gadermaier G Hilger C Holzhauser T Lidholm J et al WHO/IUIS allergen nomenclature: providing a common language. Mol Immunol. (2018) 100:3–13. 10.1016/j.molimm.2018.03.003

  • CrossRef
  • Google Scholar

• 24.

  McKenna OE Asam C Araujo GR Roulias A Goulart LR Ferreira F . How relevant is panallergen sensitization in the development of allergies?Pediatr Allergy Immunol. (2016) 27:6. 10.1111/pai.12589

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 25.

  Verdino P Westritschnig K Valenta R Keller W . The cross-reactive calcium-binding pollen allergen, phl p 7, reveals a novel dimer assembly. EMBO J. (2002) 21:19. 10.1093/emboj/cdf526

  • CrossRef
  • Google Scholar

• 26.

  Verdino P Barderas R Villalba M Westritschnig K Valenta R Rodriguez R et al Three-dimensional structure of the cross-reactive pollen allergen che a 3: visualizing cross-reactivity on the molecular surfaces of weed, grass, and tree pollen allergens. J Immunol. (2008) 180:4. 10.4049/jimmunol.180.4.2313

  • CrossRef
  • Google Scholar

• 27.

  Moya R González-Ruiz A Beitia JM Carnés J López-Matas M . Ole e 3, a candidate for in vivo diagnosis of polcalcin sensitization. Int Arch Allergy Immunol. (2021) 182:6. 10.1159/000512303

  • CrossRef
  • Google Scholar

• 28.

  Mitropoulou AN Bowen H Dodev TS Davies AM Bax HJ Beavil RL et al Structure of a patient-derived antibody in complex with allergen reveals simultaneous conventional and superantigen-like recognition. Proc Natl Acad Sci U S A. (2018) 115:37. 10.1073/pnas.1806840115

  • CrossRef
  • Google Scholar

• 29.

  Raith M Zach D Sonnleitner L Woroszylo K Focke-Tejkl M Wank H et al Rational design of a hypoallergenic phl p 7 variant for immunotherapy of polcalcin-sensitized patients. Sci Rep. (2019) 9:1. 10.1038/s41598-019-44208-0

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 30.

  Han TJ Huan F Liu M Li MS Yang Y Chen GX et al Ige epitope analysis of sarcoplasmic-calcium-binding protein, a heat-resistant allergen in crassostrea angulata. Food Funct. (2021) 12:18. 10.1039/d1fo01058a

  • CrossRef
  • Google Scholar

• 31.

  Li S Chu KH Wai CYY . Genomics of shrimp allergens and beyond. Genes (Basel. (2023) 14:12. 10.3390/genes14122145

  • CrossRef
  • Google Scholar

• 32.

  Zhu W Qin Z Huang Y Fu Q Wang H Zhang Z et al Specific detection of crustacean allergens in food: development of indirect competitive and sandwich ELISA targeting sarcoplasmic calcium binding protein. Food Biosci. (2024) 62:105093. 10.1016/j.fbio.2024.105093

  • CrossRef
  • Google Scholar

• 33.

  Zhao J Zhu W Zeng J Liu Y Li H Wang H et al Insight into the mechanism of allergenicity decreasing in recombinant sarcoplasmic calcium-binding protein from shrimp (litopenaeus vannamei) with thermal processing via spectroscopy and molecular dynamics simulation techniques. Food Res Int. (2022) 157:111427. 10.1016/j.foodres.2022.111427

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 34.

  Hu MJ Liu GY Yang Y Pan TM Liu YX Sun LC et al Cloning, expression, and the effects of processing on sarcoplasmic-calcium-binding protein: an important allergen in mud crab. J Agric Food Chem. (2017) 65:30. 10.1021/acs.jafc.7b02381

  • CrossRef
  • Google Scholar

• 35.

  Gelis S Rueda M Valero A Fernández EA Moran M Fernández-Caldas E . Shellfish allergy: unmet needs in diagnosis and treatment. J Investig Allergol Clin Immunol. (2020) 30:6. 10.18176/jiaci.0565

  • CrossRef
  • Google Scholar

• 36.

  Giovannini M Beken B Buyuktiryaki B Barni S Liccioli G Sarti L et al IgE-mediated shellfish allergy in children. Nutrients. (2023) 15:12. 10.3390/nu15122714

  • CrossRef
  • Google Scholar

• 37.

  Lopata AL Kleine-Tebbe J Kamath SD . Allergens and molecular diagnostics of shellfish allergy: part 22 of the series molecular allergology. Allergo J Int. (2016) 25:7. 10.1007/s40629-016-0124-2

  • CrossRef
  • Google Scholar

• 38.

  Han TJ Liu M Huan F Li MS Xia F Chen YY et al Identification and cross-reactivity analysis of sarcoplasmic-calcium-binding protein: a novel allergen in crassostrea angulata. J Agric Food Chem. (2020) 68:18. 10.1021/acs.jafc.0c01543

  • CrossRef
  • Google Scholar

• 39.

  Giuffrida MG Villalta D Mistrello G Amato S Asero R . ’Shrimp allergy beyond tropomyosin in Italy: clinical relevance of arginine kinase, sarcoplasmic calcium binding protein and hemocyanin. Eur Ann Allergy Clin Immunol. (2014) 46(5):172–7.

  • Pubmed Abstract
  • Google Scholar

• 40.

  Faber MA Pascal M El Kharbouchi O Sabato V Hagendorens MM Decuyper II et al Shellfish allergens: tropomyosin and beyond. Allergy. (2017) 72:6. 10.1111/all.13115

  • CrossRef
  • Google Scholar

• 41.

  Woo CK Bahna SL . Not all shellfish “allergy” is allergy!. Clin Transl Allergy. (2011) 1:1. 10.1186/2045-7022-1-3

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 42.

  Chen YY Li MS Liu M Yun X Huan F Liu QM et al Linear epitopes play an important role in the immunoglobulin G (IgG)/immunoglobulin E (IgE)-binding capacity of scy p 4. J Agric Food Chem. (2021) 69:43. 10.1021/acs.jafc.1c05464

  • CrossRef
  • Google Scholar

• 43.

  Chen Y Jin T Li M Yun X Huan F Liu Q et al Crystal structure analysis of sarcoplasmic-calcium-binding protein: an allergen in Scylla paramamosain. J Agric Food Chem. (2023) 71:2. 10.1021/acs.jafc.2c07267

  • CrossRef
  • Google Scholar

• 44.

  Nugraha R Kamath SD Johnston E Karnaneedi S Ruethers T Lopata AL . Conservation analysis of B-cell allergen epitopes to predict clinical cross-reactivity between shellfish and inhalant invertebrate allergens’. Front Immunol. (2019) 10:2676. 10.3389/fimmu.2019.02676

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 45.

  Qu X Ma Z Wu X Lv L . Recent advances of processing and detection techniques on crustacean allergens: a review. Foods. (2025) 14:2. 10.3390/foods14020285

  • CrossRef
  • Google Scholar

• 46.

  Greaser ML Gergely J . Reconstitution of troponin activity from three protein components’. J Biol Chem. (1971) 246(13):4226–33. 10.1016/S0021-9258(18)62075-7

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 47.

  Parmacek MS Leiden JM . Structure, function, and regulation of troponin C. Circulation. (1991) 84:3. 10.1161/01.cir.84.3.991

  • CrossRef
  • Google Scholar

• 48.

  Takeda S Yamashita A Maeda K Maéda Y . Structure of the core domain of human cardiac troponin in the ca(2+)-saturated form. Nature. (2003) 424:6944. 10.1038/nature01780

  • CrossRef
  • Google Scholar

• 49.

  Fusi L Brunello E Sevrieva IR Sun YB Irving M . Structural dynamics of troponin during activation of skeletal muscle. Proc Natl Acad Sci U S A. (2014) 111:12. 10.1073/pnas.1321868111

  • CrossRef
  • Google Scholar

• 50.

  Ueda T Katsuzaki H Terami H Ohtsuka H Kagawa H Murase T et al Calcium-bindings of wild type and mutant troponin cs of caenorhabditis elegans. Biochim Biophys Acta. (2001) 1548:2. 10.1016/s0167-4838(01)00234-5

  • CrossRef
  • Google Scholar

• 51.

  Cao T Thongam U Jin JP . Invertebrate troponin: insights into the evolution and regulation of striated muscle contraction. Arch Biochem Biophys. (2019) 666:40–5. 10.1016/j.abb.2019.03.013

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 52.

  Patel JR McDonald KS Wolff MR Moss RL . Ca2+ binding to troponin C in skinned skeletal muscle fibers assessed with caged Ca2+ and a Ca2+ fluorophore. Invariance of Ca2+ binding as a function of sarcomere length. J Biol Chem. (1997) 272:9. 10.1074/jbc.272.9.6018

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 53.

  Tanaka H Takahashi H Ojima T . Ca2+-binding properties and regulatory roles of lobster troponin C sites II and IV. FEBS Lett. (2013) 587:16. 10.1016/j.febslet.2013.06.042

  • CrossRef
  • Google Scholar

• 54.

  Hindley J Wünschmann S Satinover SM Woodfolk JA Chew FT Chapman MD et al Bla g 6: a troponin C allergen from blattella germanica with IgE binding calcium dependence. J Allergy Clin Immunol. (2006) 117:6. 10.1016/j.jaci.2006.02.017

  • CrossRef
  • Google Scholar

• 55.

  Jeong KY Kim CR Un S Yi MH Lee IY Park JW et al Allergenicity of recombinant troponin C from tyrophagus putrescentiae. Int Arch Allergy Immunol. (2010) 151:3. 10.1159/000242358

  • CrossRef
  • Google Scholar

• 56.

  Xia F Li M Liu Q Liao Y Li F Han X et al Molecular and immunological characterization of troponin C: an allergen from Scylla paramamosain. J Agric Food Chem. (2025) 73:5. 10.1021/acs.jafc.4c10877

  • CrossRef
  • Google Scholar

• 57.

  Chao E Kim HW Mykles DL . Cloning and tissue expression of eleven troponin-C isoforms in the American lobster, homarus americanus. Comp Biochem Physiol B Biochem Mol Biol. (2010) 157:1. 10.1016/j.cbpb.2010.05.007

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 58.

  Bauermeister K Wangorsch A Garoffo LP Reuter A Conti A Taylor SL et al Generation of a comprehensive panel of crustacean allergens from the north sea shrimp crangon crangon. Mol Immunol. (2011) 48:15–6. 10.1016/j.molimm.2011.06.216

  • CrossRef
  • Google Scholar

• 59.

  Li WY Cai ZL Zhang BP Chen JJ Ji K . Identification of an immunodominant IgE epitope of der p 39, a novel allergen of dermatophagoides pteronyssinus. World Allergy Organ J. (2022) 15:5. 10.1016/j.waojou.2022.100651

  • CrossRef
  • Google Scholar

• 60.

  Berman HM Westbrook J Feng Z Gilliland G Bhat TN Weissig H et al The protein data bank. Nucleic Acids Res. (2000) 28:1. 10.1093/nar/28.1.235

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 61.

  Virtanen T . Psoriasin and its allergenic bovine homolog bos d 3. Cell Mol Life Sci. (2006) 63:10. 10.1007/s00018-005-5598-x

  • CrossRef
  • Google Scholar

• 62.

  D'Amico F Skarmoutsou E Granata M Trovato C Rossi GA Mazzarino MC . ’S100a7: a rAMPing up AMP molecule in psoriasis. Cytokine Growth Factor Rev. (2016) 32:97–104. 10.1016/j.cytogfr.2016.01.002

  • CrossRef
  • Google Scholar

• 63.

  Liang H Li J Zhang K . Pathogenic role of S100 proteins in psoriasis. Front Immunol. (2023) 14:1191645. 10.3389/fimmu.2023.1191645

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 64.

  Vegfors J Ekman AK Stoll SW Bivik Eding C Enerbäck C . Psoriasin (S100A7) promotes stress-induced angiogenesis. Br J Dermatol. (2016) 175:6. 10.1111/bjd.14718

  • CrossRef
  • Google Scholar

• 65.

  Rautiainen J Rytkönen M Parkkinen S Pentikäinen J Linnala-Kankkunen A Virtanen T et al cDNA cloning and protein analysis of a bovine dermal allergen with homology to psoriasin. J Invest Dermatol. (1995) 105:5. 10.1111/1523-1747.ep12324309

  • CrossRef
  • Google Scholar

• 66.

  Suzuki N Yuliza Purba F Hayashi Y Nii T Yoshimura Y Isobe N . Seasonal variations in the concentration of antimicrobial components in milk of dairy cows. Anim Sci J. (2020) 91:1. 10.1111/asj.13427

  • CrossRef
  • Google Scholar

• 67.

  Gong JJ Margolis DJ Monos DS . Predictive in silico binding algorithms reveal HLA specificities and autoallergen peptides associated with atopic dermatitis. Arch Dermatol Res. (2020) 312(9):647–56. 10.1007/s00403-020-02059-0

  • Pubmed Abstract
  • CrossRef
  • Google Scholar

• 68.

  Aichberger KJ Mittermann I Reininger R Seiberler S Swoboda I Spitzauer S et al Hom s 4, an IgE-reactive autoantigen belonging to a new subfamily of calcium-binding proteins, can induce th cell type 1-mediated autoreactivity. J Immunol. (2005) 175:2. 10.4049/jimmunol.175.2.1286

  • CrossRef
  • Google Scholar

• 69.

  Natter S Seiberler S Hufnagl P Binder BR Hirschl AM Ring J et al Isolation of cDNA clones coding for IgE autoantigens with serum IgE from atopic dermatitis patients. FASEB J. (1998) 12:14. 10.1096/fasebj.12.14.1559

  • CrossRef
  • Google Scholar

• 70.

  Chruszcz M Pomés A Glesner J Vailes LD Osinski T Porebski PJ et al Molecular determinants for antibody binding on group 1 house dust mite allergens. J Biol Chem. (2012) 287:10. 10.1074/jbc.M111.311159

  • CrossRef
  • Google Scholar

• 71.

  Chruszcz M Chapman MD Vailes LD Stura EA Saint-Remy JM Minor W et al Crystal structures of mite allergens der f 1 and der p 1 reveal differences in surface-exposed residues that may influence antibody binding. J Mol Biol. (2009) 386:2. 10.1016/j.jmb.2008.12.049

  • CrossRef
  • Google Scholar

• 72.

  Kaiser L Velickovic TC Badia-Martinez D Adedoyin J Thunberg S Hallén D et al Structural characterization of the tetrameric form of the major cat allergen fel d 1. J Mol Biol. (2007) 370:4. 10.1016/j.jmb.2007.04.074

  • CrossRef
  • Google Scholar

• 73.

  Ligabue-Braun R Sachett LG Pol-Fachin L Verli H . The calcium goes meow: effects of ions and glycosylation on fel d 1, the Major cat allergen. PLoS One. (2015) 10:7. 10.1371/journal.pone.0132311

  • CrossRef
  • Google Scholar

• 74.

  Offermann LR Bublin M Perdue ML Pfeifer S Dubiela P Borowski T et al Structural and functional characterization of the hazelnut allergen cor a 8. J Agric Food Chem. (2015) 63:41. 10.1021/acs.jafc.5b03534

  • CrossRef
  • Google Scholar