Cold adaptation of zinc metalloproteases in the thermolysin family from deep sea and arctic sea ice bacteria revealed by catalytic and structural properties and molecular dynamics: new insights into relationship between conformational flexibility and hydrogen bonding.

ABSTRACT: Increased conformational flexibility is the prevailing explanation for the high catalytic efficiency of cold-adapted enzymes at low temperatures. However, less is known about the structural determinants of flexibility. We reported two novel cold-adapted zinc metalloproteases in the thermolysin family, vibriolysin MCP-02 from a deep sea bacterium and vibriolysin E495 from an Arctic sea ice bacterium, and compared them with their mesophilic homolog, pseudolysin from a terrestrial bacterium. Their catalytic efficiencies, k(cat)/K(m) (10-40 degrees C), followed the order pseudolysin < MCP-02 < E495 with a ratio of approximately 1:2:4. MCP-02 and E495 have the same optimal temperature (T(opt), 57 degrees C, 5 degrees C lower than pseudolysin) and apparent melting temperature (T(m) = 64 degrees

SUBMITTER: Xie BB 

PROVIDER: S-EPMC2666578 | biostudies-literature | 2009 Apr

REPOSITORIES: biostudies-literature