AUTHOR=Zhang Yunpeng , Wen Tong , Guo Fangfang , Geng Yuanyuan , Liu Junquan , Peng Tao , Guan Guohua , Tian Jiesheng , Li Ying , Li Jilun , Ju Jing , Jiang Wei 

TITLE=The Disruption of an OxyR-Like Protein Impairs Intracellular Magnetite Biomineralization in Magnetospirillum gryphiswaldense MSR-1

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.00208

DOI=10.3389/fmicb.2017.00208

ISSN=1664-302X

ABSTRACT=<p>Magnetotactic bacteria synthesize intracellular membrane-enveloped magnetite bodies known as magnetosomes which have been applied in biotechnology and medicine. A series of proteins involved in ferric ion transport and redox required for magnetite formation have been identified but the knowledge of magnetosome biomineralization remains very limited. Here, we identify a novel OxyR homolog (named OxyR-Like), the disruption of which resulted in low ferromagnetism and disfigured nano-sized iron oxide crystals. High resolution-transmission electron microscopy showed that these nanoparticles are mainly composed of magnetite accompanied with ferric oxide including α-Fe<sub>2</sub>O<sub>3</sub> and 𝜀-Fe<sub>2</sub>O<sub>3</sub>. Electrophoretic mobility shift assay and DNase I footprinting showed that OxyR-Like binds the conserved 5′-GATA-N{9}-TATC-3′ region within the promoter of pyruvate dehydrogenase (<italic>pdh</italic>) complex operon. Quantitative real-time reverse transcriptase PCR indicated that not only the expression of <italic>pdh</italic> operon but also genes related to magnetosomes biosynthesis and tricarboxylic acid cycle decreased dramatically, suggesting a link between carbon metabolism and magnetosome formation. Taken together, our results show that OxyR-Like plays a key role in magnetosomes formation.</p>