Crystal structure of CHO reductase, a member of the aldo-keto reductase superfamily

Abstract

Chinese hamster ovary (CHO) re-ductase is an enzyme belonging to the aldo-keto reductase (AKR) superfamily that is induced by the aldehyde-containing protease inhibitor ALLN (In-oue, 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 nicotin-amide adenine dinucleotide phosphate (NADP) to 2.4 A ˚ resolution. Similar to aldose reductase and other AKRs, CHO reductase is an / TIM barrel enzyme with cofactor bound in an extended confor-mation. 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 sub-strates. 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.

Inhibitor selectivity between aldo–keto reductase superfamily members AKR1B10 and AKR1B1: Role of Trp112 (Trp111)

“…In the holo‐AKR1B9 structure (Chinese hamster ovary reductase, PDB ID: 1C9W), the corresponding residue (Trp111) is located at a transitional position between the “B1‐position” and the “B10‐position”, Fig. S4) [22].…”

Preparation and characterization of polyclonal antibodies against ARL-1 protein

“…CHO reductase mRNA was quite abundant in the urinary bladder and the jejunum, this gene was also expressed in the testis and the ovary. However, CHO reductase mRNA was not detectable in brain, heart, liver, kidney, and muscle [45][46][47] . ARL-1 was not expressed in many tissues.…”

All in the family: aldose reductase and closely related aldo-keto reductases

“…Lys-77 is in turn salt linked to carboxylate of Asp-43. This general arrangement is conserved among other AKR subfamily enzymes whose structures have been solved, including AR/AKR1A1 [23], 3a-hydroxysteroid dehydrogenase AKR 1C9 [24], FR-1 AKR1B8 [25] and CHO reductase AKR1B9 [26]. While the overall structural features of the AKR family members are well conserved, subtle differences near the C-terminal domain are thought to be responsible for differences in substrate specificity among closely related enzymes (see below).…”