title: Homology modeling of rho-crystallin from bullfrog (Rana catesbeiana) lens.
abstract: 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.
authors.affiliation: Department of Biochemistry, University of Karachi, Karachi 75270, Pakistan. szed@super.net.pk
authors.forename: Shamshad
authors.initials: S
authors.lastname: Zarina
authors.forename: Zafar H
authors.initials: ZH
authors.lastname: Zaidi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D003459:Crystallins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007908:Lens, Crystalline / Q000737:chemistry*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D020033:Protein Isoforms / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D017434:Protein Structure, Tertiary; D011892:Rana catesbeiana / Q000378:metabolism*; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013329:Structure-Activity Relationship
chemical_list: D003459:Crystallins; D020033:Protein Isoforms