Protein Science, Vol 9, Issue 10 1898-1904, Copyright © 2000 by The Protein Society

Crystal structure of an in vivo HIV-1 protease mutant in complex with saquinavir: insights into the mechanisms of drug resistance [In Process Citation]

L Hong, XC Zhang, JA Hartsuck and J Tang
Protein Studies Program, Oklahoma Medical Research Foundation, University of Oklahoma Health Sciences Center, Oklahoma City 73104, USA.

Saquinavir is a widely used HIV-1 protease inhibitor drug for AIDS therapy. Its effectiveness, however, has been hindered by the emergence of resistant mutations, a common problem for inhibitor drugs that target HIV-1 viral enzymes. Three HIV-1 protease mutant species, G48V, L90M, and G48V/L90M double mutant, are associated in vivo with saquinavir resistance by the enzyme (Jacobsen et al., 1996). Kinetic studies on these mutants demonstrate a 13.5-, 3-, and 419-fold increase in Ki values, respectively, compared to the wild-type enzyme (Ermolieff J, Lin X, Tang J, 1997, Biochemistry 36:12364-12370). To gain an understanding of how these mutations modulate inhibitor binding, we have solved the HIV-1 protease crystal structure of the G48V/L90M double mutant in complex with saquinavir at 2.6 A resolution. This mutant complex is compared with that of the wild-type enzyme bound to the same inhibitor (Krohn A, Redshaw S, Richie JC, Graves BJ, Hatada MH, 1991, J Med Chem 34:3340-3342). Our analysis shows that to accommodate a valine side chain at position 48, the inhibitor moves away from the protease, resulting in the formation of larger gaps between the inhibitor P3 subsite and the flap region of the enzyme. Other subsites also demonstrate reduced inhibitor interaction due to an overall change of inhibitor conformation. The new methionine side chain at position 90 has van der Waals interactions with main-chain atoms of the active site residues resulting in a decrease in the volume and the structural flexibility of S1/S1' substrate binding pockets. Indirect interactions between the mutant methionine side chain and the substrate scissile bond or the isostere part of the inhibitor may differ from those of the wild-type enzyme and therefore may facilitate catalysis by the resistant mutant.
CiteULike    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				H. E. Klei, K. Kish, P.-F. M. Lin, Q. Guo, J. Friborg, R. E. Rose, Y. Zhang, V. Goldfarb, D. R. Langley, M. Wittekind, et al. X-Ray Crystal Structures of Human Immunodeficiency Virus Type 1 Protease Mutants Complexed with Atazanavir J. Virol., September 1, 2007; 81(17): 9525 - 9535. [Abstract] [Full Text] [PDF]

				M. Amano, Y. Koh, D. Das, J. Li, S. Leschenko, Y.-F. Wang, P. I. Boross, I. T. Weber, A. K. Ghosh, and H. Mitsuya A Novel Bis-Tetrahydrofuranylurethane-Containing Nonpeptidic Protease Inhibitor (PI), GRL-98065, Is Potent against Multiple-PI-Resistant Human Immunodeficiency Virus In Vitro Antimicrob. Agents Chemother., June 1, 2007; 51(6): 2143 - 2155. [Abstract] [Full Text] [PDF]

				J. E. Foulkes, M. Prabu-Jeyabalan, D. Cooper, G. J. Henderson, J. Harris, R. Swanstrom, and C. A. Schiffer Role of Invariant Thr80 in Human Immunodeficiency Virus Type 1 Protease Structure, Function, and Viral Infectivity J. Virol., July 15, 2006; 80(14): 6906 - 6916. [Abstract] [Full Text] [PDF]

				J. Yanchunas Jr., D. R. Langley, L. Tao, R. E. Rose, J. Friborg, R. J. Colonno, and M. L. Doyle Molecular Basis for Increased Susceptibility of Isolates with Atazanavir Resistance-Conferring Substitution I50L to Other Protease Inhibitors Antimicrob. Agents Chemother., September 1, 2005; 49(9): 3825 - 3832. [Abstract] [Full Text] [PDF]

				K. Wittayanarakul, O. Aruksakunwong, S. Saen-oon, W. Chantratita, V. Parasuk, P. Sompornpisut, and S. Hannongbua Insights into Saquinavir Resistance in the G48V HIV-1 Protease: Quantum Calculations and Molecular Dynamic Simulations Biophys. J., February 1, 2005; 88(2): 867 - 879. [Abstract] [Full Text] [PDF]

				F. Clavel and A. J. Hance HIV Drug Resistance N. Engl. J. Med., March 4, 2004; 350(10): 1023 - 1035. [Full Text] [PDF]

				M. D. Shenderovich, R. M. Kagan, P. N.R. Heseltine, and K. Ramnarayan Structure-based phenotyping predicts HIV-1 protease inhibitor resistance Protein Sci., August 1, 2003; 12(8): 1706 - 1718. [Abstract] [Full Text] [PDF]

				S. Piana, P. Carloni, and U. Rothlisberger Drug resistance in HIV-1 protease: Flexibility-assisted mechanism of compensatory mutations Protein Sci., October 1, 2002; 11(10): 2393 - 2402. [Abstract] [Full Text] [PDF]

				N. Beerenwinkel, B. Schmidt, H. Walter, R. Kaiser, T. Lengauer, D. Hoffmann, K. Korn, and J. Selbig Diversity and complexity of HIV-1 drug resistance: A bioinformatics approach to predicting phenotype from genotype PNAS, June 11, 2002; 99(12): 8271 - 8276. [Abstract] [Full Text] [PDF]

				P. F. Egea, A. Mitschler, and D. Moras Molecular Recognition of Agonist Ligands by RXRs Mol. Endocrinol., May 1, 2002; 16(5): 987 - 997. [Abstract] [Full Text] [PDF]