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Escherichia coli multiple [Ni–Fe]‐hydrogenases are sensitive to osmotic stress during glycerol fermentation but at different pHs
Author(s) -
Trchounian Karen,
Trchounian Armen
Publication year - 2013
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2013.09.016
Subject(s) - escherichia coli , fermentation , osmotic shock , glycerol , biochemistry , biology , enzyme , osmolyte , enterobacteriaceae , osmoregulation , mutant , food science , gene , ecology , salinity
Escherichia coli evolves H 2 via multiple [Ni–Fe]‐hydrogenases (Hyd). This activity under hyper‐ and hypo‐osmotic stress was investigated with mutants lacking different Hyd enzymes during glycerol fermentation. Inhibitory effects of hypo‐stress on H 2 production was stronger at pH 6.5 in wild type and mutants except fhlA , which encodes a transcriptional activator for Hyd‐3, compared with the effects of N , N ′‐dicyclohexylcarbodiimide. These results indicate that Hyd‐3 and Hyd‐4 are osmosensitive at pH 7.5. Hyd‐4 and FhlA are implicated in osmotic stress response at pH 6.5. Hyd‐1 and FhlA might be osmosensitive at pH 5.5. Thus, osmosensitivity of Hyd enzymes is a novel property that depends on pH. This is significant for mechanisms of cell osmoregulation and H 2 production biotechnology when glycerol is used as a fermentation substrate.