title: Comparative study on stabilization mechanism of monomeric cytochrome c5from deep-sea piezophilic Shewanella violacea.
abstract: Monomeric cytochrome c5from 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 SVcytc5crystal 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 SVcytc5was isolated from a deep-sea piezophilic bacterium, the present comparative study indicates that adaptation of monomeric SVcytc5to high pressure environments results in stabilization against heat.
authors.affiliation: a Graduate School of Biosphere Science , Hiroshima University , Higashi-Hiroshima , Japan.
authors.forename: Misa
authors.initials: M
authors.lastname: Masanari
authors.affiliation: a Graduate School of Biosphere Science , Hiroshima University , Higashi-Hiroshima , Japan.
authors.forename: Sotaro
authors.initials: S
authors.lastname: Fujii
authors.affiliation: b Graduate School of Pharmaceutical Sciences , Osaka University , Suita , Japan.
authors.forename: Kazuki
authors.initials: K
authors.lastname: Kawahara
authors.affiliation: b Graduate School of Pharmaceutical Sciences , Osaka University , Suita , Japan.
authors.forename: Hiroya
authors.initials: H
authors.lastname: Oki
authors.affiliation: b Graduate School of Pharmaceutical Sciences , Osaka University , Suita , Japan.
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Tsujino
authors.affiliation: c Graduate School of Engineering , Osaka University , Suita , Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Maruno
authors.affiliation: c Graduate School of Engineering , Osaka University , Suita , Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: b Graduate School of Pharmaceutical Sciences , Osaka University , Suita , Japan.
authors.forename: Tadayasu
authors.initials: T
authors.lastname: Ohkubo
authors.affiliation: d Graduate School of Science Technology and Innovation , Kobe University , Kobe , Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Wakai
authors.affiliation: a Graduate School of Biosphere Science , Hiroshima University , Higashi-Hiroshima , Japan.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Sambongi
mesh_terms: D018360:Crystallography, X-Ray; D045304:Cytochromes c / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D004795:Enzyme Stability; D006418:Heme / Q000737:chemistry; D006860:Hydrogen Bonding; D008958:Models, Molecular; D016296:Mutagenesis; D009154:Mutation; D011487:Protein Conformation; D020592:Shewanella / Q000201:enzymology*; D013696:Temperature
chemical_list: D006418:Heme; D045304:Cytochromes c
keywords: Shewanella violacea; crystal structure; cytochrome c5; pressure environment; stability