Comparative study on stabilization mechanism of monomeric cytochrome c5 from deep-sea piezophilic Shewanella violacea

• Published in: Bioscience, biotechnology, and biochemistry Vol. 80; no. 12; pp. 2365 - 2370
• Main Authors: Masanari, Misa, Fujii, Sotaro, Kawahara, Kazuki, Oki, Hiroya, Tsujino, Hirofumi, Maruno, Takahiro, Kobayashi, Yuji, Ohkubo, Tadayasu, Wakai, Satoshi, Sambongi, Yoshihiro
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.12.2016
• Subjects: crystal structure; cytochrome c; pressure environment; Shewanella violacea; stability
• ISSN: 0916-8451; 1347-6947
• DOI: 10.1080/09168451.2016.1232155

Monomeric cytochrome c 5 from deep-sea piezophilic Shewanella violacea (SVcytc 5 ) was stable against heat and denaturant compared with the homologous protein from shallow-sea piezo-sensitive Shewanella livingstonensis (SLcytc 5 ). Here, the SVcytc 5 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 SLcytc 5 , 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 SVcytc 5 was isolated from a deep-sea piezophilic bacterium, the present comparative study indicates that adaptation of monomeric SVcytc 5 to high pressure environments results in stabilization against heat. Structure of Shewanella violaceacy to chrome c 5 revealed that Lys-50 on a flexible loop was responsible for its stability.