Mechanism of drug resistance revealed by the crystal structure of the unliganded HIV-1 protease with F53L mutation.
Mutations in HIV-1 protease (PR) that produce resistance to antiviral PR inhibitors are a major problem in AIDS therapy. The mutation F53L arising from antiretroviral therapy was introduced into the flexible flap region of the wild-type PR to study its effect and potential role in developing drug resistance. Compared to wild-type PR, PR(F53L) showed lower (15%) catalytic efficiency, 20-fold weaker inhibition by the clinical drug indinavir, and reduced dimer stability, while the inhibition constants of two peptide analog inhibitors were slightly lower than those for PR. The crystal structure of PR(F53L) was determined in the unliganded form at 1.35 Angstrom resolution in space group P4(1)2(1)2. The tips of the flaps in PR(F53L) had a wider separation than in unliganded wild-type PR, probably due to the absence of hydrophobic interactions of the side-chains of Phe53 and Ile50'. The changes in interactions between the flaps agreed with the reduced stability of PR(F53L) relative to wild-type PR. The altered flap interactions in the unliganded form of PR(F53L) suggest a distinct mechanism for drug resistance, which has not been observed in other common drug-resistant mutants.
Department of Biology, Molecular Basis of Disease Program, Georgia State University, Atlanta, GA 30303, USA.
Fengling
F
Liu
Andrey Y
AY
Kovalevsky
John M
JM
Louis
Peter I
PI
Boross
Yuan-Fang
YF
Wang
Robert W
RW
Harrison
Irene T
IT
Weber
D020134:Catalytic Domain / Q000235:genetics; D018360:Crystallography, X-Ray; D024882:Drug Resistance, Viral / Q000235:genetics*; D004795:Enzyme Stability / Q000235:genetics; D015658:HIV Infections / Q000188:drug therapy / Q000821:virology; D016333:HIV Protease / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D017320:HIV Protease Inhibitors / Q000494:pharmacology; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D066298:In Vitro Techniques; D019469:Indinavir / Q000494:pharmacology; D007700:Kinetics; D008024:Ligands; D008958:Models, Molecular; D017354:Point Mutation; D011487:Protein Conformation; D055672:Static Electricity
D017320:HIV Protease Inhibitors; D008024:Ligands; D019469:Indinavir; D016333:HIV Protease