Comparative study on stabilization mechanism of monomeric cytochrome c5 from deep-sea piezophilic Shewanella violacea. Issue 12 (1st December 2016) - Masanari, Misa
Abstract: Monomeric cytochrome c 5 from deep-sea piezophilic Shewanella violacea (SVcyt c 5 ) was stable against heat and denaturant compared with the homologous protein from shallow-sea piezo-sensitive Shewanella livingstonensis (SLcyt c 5 ). Here, the SVcyt c 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 SLcyt c 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 SVcyt c 5 was isolated from a deep-sea piezophilic bacterium, the present comparative study indicates that adaptation of monomeric SVcyt c 5 to high pressure environments results in stabilization against heat. Graphical abstract: : Structure of Shewanella violacea cy to chrome c 5 revealed that Lys-50 on a flexible loop was responsible for its stability.