How Escherichia coli is equipped to oxidize hydrogen under different redox conditions.

Journal article

The enterobacterium Escherichia coli synthesizes two H(2) uptake enzymes, Hyd-1 and Hyd-2. We show using precise electrochemical kinetic measurements that the properties of Hyd-1 and Hyd-2 contrast strikingly, and may be individually optimized to function under distinct environmental conditions. Hyd-2 is well suited for fast and efficient catalysis in more reducing environments, to the extent that in vitro it behaves as a bidirectional hydrogenase. In contrast, Hyd-1 is active for H(2) oxidation under more oxidizing conditions and cannot function in reverse. Importantly, Hyd-1 is O(2) tolerant and can oxidize H(2) in the presence of air, whereas Hyd-2 is ineffective for H(2) oxidation under aerobic conditions. The results have direct relevance for physiological roles of Hyd-1 and Hyd-2, which are expressed in different phases of growth. The properties that we report suggest distinct technological applications of these contrasting enzymes.

Authors: Lukey, M; Parkin, A; Roessler, M; Murphy, B; Harmer, J

• Publication status: Published
• Journal: Journal of biological chemistry
• Volume: 285
• Issue: 6
• Pages: 3928-3938
• Publication date: 2010-02-01
• DOI: 10.1074/jbc.m109.067751
• EISSN: 1083-351X
• ISSN: 0021-9258
• Language: English
• Keywords: Oxidation-Reduction; Hydrogen; Escherichia coli; Escherichia coli Proteins; Spectrophotometry; Aerobiosis; Protein Subunits; Dose-Response Relationship, Drug; Oxygen; Oxidoreductases; Electrochemical Techniques