W0203

Analysis of HIV-1 Protease Mutants to Understand Mechanisms of Resistance. Wang Y.-F.¹, Mahalingam B.¹, Tie Y.¹, Boross P.^1,2, Liu F.¹, Louis J. M.³, Tozser J.², Harrison R. W.^1,4, Weber I. T.¹ ,¹Dept. of Biology, Georgia State Univ., Atlanta, GA, USA; ²Dept. of Biochemistry and Molecular Biology, Faculty of Medicine, Debrecen Univ., Debrecen, Hungary; ³Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, The National Institutes of Health, Bethesda, MD, USA and ⁴Dept. of Computer Science, Georgia State Univ. Atlanta, GA, USA

The therapeutic efficacy of inhibitors of HIV-1 protease is limited due to the rapid selection of drug resistant mutants of the protease. Drug resistance also involves mutations of the protease cleavage sites NC-p1 and p1-p6 in the Gag precursor. Resistant mutants of HIV-1 protease with single amino acid substitutions have been examined using enzyme kinetics and crystallography in order to understand the molecular basis for resistance. Mutants with either increased or decreased catalytic activity, inhibition or stability relative to the wild type enzyme have been observed. Crystal structures of mutant protease complexes with substrate analogs were determined at resolutions of up to 1.4 Å in order to define the molecular changes associated with the altered activities. The result of detailed structural and kinetic studies is that mutations show a range of effects that depend on the specific combination of mutant with substrate or inhibitor (1). Mutation of rate-limiting cleavage sites can partly compensate for the reduced catalytic activity of mutant proteases (2).

1. Mahalingam, B., Louis, J.M., Hung, J., Harrison, R.W. and Weber, I.T. “Structural implications of drug resistant mutants of HIV-1 protease: High resolution crystal structures of the mutant protease/substrate analog complexes.” (2001) Proteins, 43, 455-464.

2. Feher, A., Weber, I.T., Bagossi, P., Boross, P., Mahalingam, B., Louis, J.M., Torshin, I.Y., Harrison, R.W. and Tozser, J. Effect of sequence polymorphism and drug resistance on two HIV-1 Gag processing sites. (2002) Eur. J. Biochem. 269, 4114-4129.