Homology modeling of rho-crystallin from bullfrog (Rana catesbeiana) lens.

rho-Crystallins are major protein component found in the eye lenses of frogs of the genus Rana. Structural analysis has indicated that frog rho-crystallins belong to aldo-keto reductase superfamily (AKRs) which include aldehyde and aldose reductases, prostaglandin F synthase and several detoxification enzymes. Members of AKRs catalyze the oxidation-reduction reaction over a range of substrates using NAD(P)(H) as a cofactor. In spite of higher structural similarity with AKRs and cofactor binding affinity, the rho-crystallins were found to be catalytically inactive. This study presents comparative or homology modeling of rho-crystallin from bullfrog (Rana catesbeiana) in presence and absence of cofactor NADP and a competitive inhibitor, testosterone. The predicted models are explored to examine the catalytic cleft, cofactor binding affinity characteristics and substrate binding pocket.