The Crystal Structure of Rat Liver Akr7A1: A Dimeric Member of the Aldo-Keto Reductase SuperfamilyKozma, E., Brown, E., Ellis, E.M., Lapthorn, A.J.
(2002) J.Biol.Chem. 277: 16285
- PubMed: 11839745
- DOI: 10.1074/jbc.M110808200
- PubMed Abstract:
- An Ethoxyquin-Inducible Aldehyde Reductase from Rat Liver that Metabolizes Aflatoxin B1 Defines a Subfamily of Aldo-Keto Reductases
Ellis, E.M.,Judah, D.J.,Neal, G.E.,Hayes, J.D.
(1993) Proc.Natl.Acad.Sci.USA 90: 10350
The structure of the rat liver aflatoxin dialdehyde reductase (AKR7A1) has been solved to 1.38-A resolution. Although it shares a similar alpha/beta-barrel structure with other members of the aldo-keto reductase superfamily, AKR7A1 is the first dimer ...
The structure of the rat liver aflatoxin dialdehyde reductase (AKR7A1) has been solved to 1.38-A resolution. Although it shares a similar alpha/beta-barrel structure with other members of the aldo-keto reductase superfamily, AKR7A1 is the first dimeric member to be crystallized. The crystal structure also reveals details of the ternary complex as one subunit of the dimer contains NADP(+) and the inhibitor citrate. Although the underlying catalytic mechanism appears similar to other aldo-keto reductases, the substrate-binding pocket contains several charged amino acids (Arg-231 and Arg-327) that distinguish it from previously characterized aldo-keto reductases with respect to size and charge. These differences account for the substrate specificity for 4-carbon acid-aldehydes such as succinic semialdehyde and 2-carboxybenzaldehyde as well as for the idiosyncratic substrate aflatoxin B(1) dialdehyde of this subfamily of enzymes. Structural differences between the AKR7A1 ternary complex and apoenzyme reveal a significant hinged movement of the enzyme involving not only the loops of the structure but also parts of the alpha/beta-barrel most intimately involved in cofactor binding.
Department of Chemistry, University of Glasgow, Glasgow G12 8QQ, United Kingdom.