Comparative study on stabilization mechanism of monomeric cytochrome c5 from deep-sea piezophilic Shewanella violacea |
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| Authors: | Misa Masanari Sotaro Fujii Kazuki Kawahara Hiroya Oki Hirofumi Tsujino Takahiro Maruno |
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| Institution: | 1. Graduate School of Biosphere Science, Hiroshima University, Higashi-Hiroshima, Japan;2. Graduate School of Pharmaceutical Sciences, Osaka University, Suita, Japan;3. Graduate School of Engineering, Osaka University, Suita, Japan |
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| Abstract: | Monomeric cytochrome c5 from deep-sea piezophilic Shewanella violacea (SVcytc5) was stable against heat and denaturant compared with the homologous protein from shallow-sea piezo-sensitive Shewanella livingstonensis (SLcytc5). Here, the SVcytc5 crystal structure revealed that the Lys-50 side chain on the flexible loop formed a hydrogen bond with heme whereas that of corresponding hydrophobic Leu-50 could not form such a bond in SLcytc5, which appeared to be one of possible factors responsible for the difference in stability between the two proteins. This structural insight was confirmed by a reciprocal mutagenesis study on the thermal stability of these two proteins. As SVcytc5 was isolated from a deep-sea piezophilic bacterium, the present comparative study indicates that adaptation of monomeric SVcytc5 to high pressure environments results in stabilization against heat. |
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| Keywords: | cytochrome c5 Shewanella violacea crystal structure stability pressure environment |
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