Pressure adaptation of 3-isopropylmalate dehydrogenase from an extremely piezophilic bacterium is attributed to a single amino acid substitution.
Extremophiles 2016;
20:177-86. [PMID:
26847201 DOI:
10.1007/s00792-016-0811-4]
[Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 01/15/2016] [Indexed: 10/22/2022]
Abstract
3-Isopropylmalate dehydrogenase (IPMDH) from the extreme piezophile Shewanella benthica (SbIPMDH) is more pressure-tolerant than that from the atmospheric pressure-adapted Shewanella oneidensis (SoIPMDH). To understand the molecular mechanisms of this pressure tolerance, we analyzed mutated enzymes. The results indicate that only a single mutation at position 266, corresponding to Ala (SbIPMDH) and Ser (SoIPMDH), essentially affects activity under higher-pressure conditions. Structural analyses of SoIPMDH suggests that penetration of three water molecules into the cleft around Ser266 under high-pressure conditions could reduce the activity of the wild-type enzyme; however, no water molecule is observed in the Ala266 mutant.
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