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Improved O 2 ‐tolerance in variants of a H 2 ‐evolving [NiFe]‐hydrogenase from Klebsiella oxytoca HP1
Author(s) -
Huang Gang-Feng,
Wu Xiao-Bing,
Bai Li-Ping,
Liu Ke,
Jiang Li-Jing,
Long Min-Nan,
Chen Qing-Xi
Publication year - 2015
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.2015.02.027
Subject(s) - klebsiella oxytoca , hydrogenase , chemistry , protein subunit , oxygen , amino acid , biophysics , biochemistry , biology , gene , escherichia coli , enterobacteriaceae , enzyme , organic chemistry
In this study, we investigated the mechanism of O 2 tolerance of Klebsiella oxytoca HP1 H 2 ‐evolving hydrogenase 3 (KHyd3) by mutational analysis and three‐dimensional structure modeling. Results revealed that certain surface amino acid residues of KHyd3 large subunit, in particular those at the outer entrance of the gas channel, have a visible effect on its oxygen tolerance. Additionally, solution pH, immobilization and O 2 partial pressure also affect KHyd3 O 2 ‐tolerance to some extent. We propose that the extent of KHyd3 O 2 ‐tolerance is determined by a balance between the rate of O 2 access to the active center through gas channels and the deoxidation rate of the oxidized active center. Based on our findings, two higher O 2 ‐tolerant KHyd3 mutations G300E and G300M were developed.