Crystal Structure of an Alcohol Dehydrogenase from the Extreme Thermophile Thermoanaerobium brockii.
Abstract
The crystal structure of a thermophilic alcohol dehydrogenase (TBAD) has been determined in complex with sec-butanol as substrate to a resolution of 3.0 A. The enzyme is from Thermoanaerobacter brockii, a bacterium isolated from hot springs in Yellowstone National Park. This tetrameric enzyme has a melting temperature of 98 C. The structure consists of two domains, the catalytic domain and the cofactor-binding domain, with the active site located in a deep cleft at the domain interface. Factors important for the thermostability have been deduced by comparison with the crystal structure of a highly homologous mesophilic alcohol dehydrogenase from Clostridium beijerinckii (CBAD). The thermophilic enzyme has a more hydrophilic exterior, a more hydrophobic interior. a smaller surface area, more prolines, alanines, and less serines than CBAD. Furthermore, in the thermophilic enzyme the number of all types of intersubunit interactions is increased: more salt bridges, hydrogen bonds and hydrophobic interactions. All these effects combined can account for the 32 deg C higher melting temperature of the thermophilic enzyme.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 16, 1998
- Accession Number
- ADA358217
Entities
People
- Menachem Shoham
Organizations
- Case Western Reserve University