title: Ligand modifications to reduce the relative resistance of multi-drug resistant HIV-1 protease.
abstract: Proper proteolytic processing of the HIV-1 Gag/Pol polyprotein is required for HIV infection and viral replication. This feature has made HIV-1 protease an attractive target for antiretroviral drug design for the treatment of HIV-1 infected patients. To examine the role of the P1 and P1'positions of the substrate in inhibitory efficacy of multi-drug resistant HIV-1 protease 769 (MDR 769), we performed a series of structure-function studies. Using the original CA/p2 cleavage site sequence, we generated heptapeptides containing one reduced peptide bond with an L to F and A to F double mutation at P1 and P1' (F-r-F), and an A to F at P1' (L-r-F) resulting in P1/P1' modified ligands. Here, we present an analysis of co-crystal structures of CA/p2 F-r-F, and CA/p2 L-r-F in complex with MDR 769. To examine conformational changes in the complex structure, molecular dynamic (MD) simulations were performed with MDR769-ligand complexes. MD trajectories show the isobutyl group of both the lopinavir analog and the CA/p2 L-r-F substrate cause a conformational change of in the active site of MDR 769. IC50 measurements suggest the non identical P1/P1' ligands (CA/p2 L-r-F and lopinavir analog) are more effective against MDR proteases as opposed to identical P1/P1'ligands. Our results suggest that a non identical P1/P1'composition may be more favorable for the inhibition of MDR 769 as they induce conformational changes in the active site of the enzyme resulting in disruption of the two-fold symmetry of the protease, thus, stabilizing the inhibitor in the active site.
authors.affiliation: Department of Biochemistry and Molecular Biology, School of Medicine, Wayne State University, Detroit, MI 48201, USA.
authors.forename: Tamaria G
authors.initials: TG
authors.lastname: Dewdney
authors.forename: Yong
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Liu
authors.forename: Shiv K
authors.initials: SK
authors.lastname: Sharma
authors.forename: Samuel J
authors.initials: SJ
authors.lastname: Reiter
authors.forename: Joseph S
authors.initials: JS
authors.lastname: Brunzelle
authors.forename: Iulia A
authors.initials: IA
authors.lastname: Kovari
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Woster
authors.forename: Ladislau C
authors.initials: LC
authors.lastname: Kovari
mesh_terms: D018432:Drug Resistance, Multiple; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology*; D016333:HIV Protease / Q000737:chemistry / Q000378:metabolism*; D017320:HIV Protease Inhibitors / Q000737:chemistry* / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology*; D006801:Humans; D008024:Ligands; D008958:Models, Molecular; D011487:Protein Conformation
chemical_list: D017320:HIV Protease Inhibitors; D008024:Ligands; D016333:HIV Protease; C514803:p16 protease, Human immunodeficiency virus 1
keywords: Crystallography; Drug design; Drug resistance; HIV-1 protease; Lopinavir