Studies on human aldose reductase

Abstract

Protein folding is a fundamental process in living systems. Most globular proteins exist in the folded state to carry out their functions. Preserving the folded state is crucial for proteins as translation-errors, mutations, and changes in the cellular environment may easily lead to misfolding or aggregation. In present work, the equilibrium unfolding of aldose reductase (AR) was studied using spectroscopic techniques. During chemical-induced equilibrium unfolding studies of AR, an intermediate state was identified at 3.5-4.0 M urea and 0.7-2.0 M gdnhcl. In terms of free energy change (and#916;G) value, the intermediate state was close to the native state, which might have physiological implications as AR functions in osmotic-stress conditions during chronic hyperglycemia. Another part of the work deals with the dynamics of a glutathione analog, [and#947;-glutamyl-S-(1,2-di-carboxyethyl) cysteinyl-glycine, DCEG], into the binding pocket of AR. DCEG is a competitive inhibitor of AR, and its crystal structure in complex with AR and NADPH has been determined. From the analysis of molecular dynamics (MD) simulation, it was found that AR specifically recognizes only a part of the glutathione backbone. During the MD simulation, DCEG mimicked the substrate inside the binding pocket of AR, explaining the competitive inhibition by DCEG. AR has been a drug target for secondary diabetic complications, and in spite of intensive search for an AR inhibitor as a drug, there is hardly any success. In present work, virtual screening was performed to find new scaffolds of small molecules that may provide potential leads for structure-based drug design. newline