Premium
Crystal structure of CHO reductase, a member of the aldo‐keto reductase superfamily
Author(s) -
Ye Qilu,
Hyndman David,
Li Xuhong,
Flynn T. Geoffrey,
Jia Zongchao
Publication year - 2000
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/(sici)1097-0134(20000101)38:1<41::aid-prot5>3.0.co;2-m
Subject(s) - aldo keto reductase , aldose reductase , reductase , aldehyde reductase , chinese hamster ovary cell , cofactor , biochemistry , 7 dehydrocholesterol reductase , stereochemistry , chemistry , nad+ kinase , active site , enzyme , biology , receptor
Chinese hamster ovary (CHO) reductase is an enzyme belonging to the aldo‐keto reductase (AKR) superfamily that is induced by the aldehyde‐containing protease inhibitor ALLN (Inoue, Sharma, Schimke, et al., J Biol Chem 1993;268:5894). It shows 70% sequence identity to human aldose reductase (Hyndman, Takenoshita, Vera, et al., J Biol Chem 1997;272:13286), which is a target for drug design because of its implication in diabetic complications. We have determined the crystal structure of CHO reductase complexed with nicotinamide adenine dinucleotide phosphate (NADP) + to 2.4 Å resolution. Similar to aldose reductase and other AKRs, CHO reductase is an α/β TIM barrel enzyme with cofactor bound in an extended conformation. All key residues involved in cofactor binding are conserved with respect to other AKR members. CHO reductase shows a high degree of sequence identity (91%) with another AKR member, FR‐1 (mouse fibroblast growth factor‐regulated protein), especially around the variable C‐terminal end of the protein and has a similar substrate binding pocket that is larger than that of aldose reductase. However, there are distinct differences that can account for differences in substrate specificity. Trp111, which lies horizontal to the substrate pocket in all other AKR members is perpendicular in CHO reductase and is accompanied by movement of Leu300. This coupled with movement of loops A, B, and C away from the active site region accounts for the ability of CHO reductase to bind larger substrates. The position of Trp219 is significantly altered with respect to aldose reductase and appears to release Cys298 from steric constraints. These studies show that AKRs such as CHO reductase are excellent models for examining the effects of subtle changes in amino acid sequence and alignment on binding and catalysis. Proteins 2000;38:41–48. ©2000 Wiley‐Liss, Inc.