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

Biosci Biotechnol Biochem. 2016 Dec;80(12):2365-2370. doi: 10.1080/09168451.2016.1232155. Epub 2016 Sep 20.

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.

Keywords: Shewanella violacea; crystal structure; cytochrome c5; pressure environment; stability.

Publication types

  • Comparative Study

MeSH terms

  • Crystallography, X-Ray
  • Cytochromes c / chemistry*
  • Cytochromes c / genetics
  • Cytochromes c / metabolism
  • Enzyme Stability
  • Heme / chemistry
  • Hydrogen Bonding
  • Models, Molecular
  • Mutagenesis
  • Mutation
  • Protein Conformation
  • Shewanella / enzymology*
  • Temperature

Substances

  • Heme
  • Cytochromes c