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Article
Curling of flap tips in HIV-1 protease as a mechanism for substrate entry and tolerance of drug resistance
Biochemistry and Molecular Pharmacology Publications and Presentations
  • Walter Robert Peter Scott
  • Celia A. Schiffer, University of Massachusetts Medical School
UMMS Affiliation
Department of Biochemistry and Molecular Pharmacology
Publication Date
2-24-2001
Document Type
Article
Subjects
Binding Sites; Computer Simulation; Conserved Sequence; Drug Resistance, Microbial; Glycine; HIV Protease; HIV-1; Humans; Isoleucine; Ligands; Methionine; Models, Molecular; Mutagenesis, Site-Directed; Nuclear Magnetic Resonance, Biomolecular; Peptide Fragments; Phenylalanine; Protein Conformation; Solvents; Static Electricity; Substrate Specificity; Thermodynamics
Abstract
BACKGROUND: The human immunodeficiency virus type 1 (HIV-1) protease is an essential viral protein that is a major drug target in the fight against Acquired Immune Deficiency Syndrome (AIDS). Access to the active site of this homodimeric enzyme is gained when two large flaps, one from each monomer, open. The flap movements are therefore central to the function of the enzyme, yet determining how these flaps move at an atomic level has not been experimentally possible. RESULTS: In the present study, we observe the flaps of HIV-1 protease completely opening during a 10 ns solvated molecular dynamics simulation starting from the unliganded crystal structure. This movement is on the time scale observed by Nuclear Magnetic Resonance (NMR) relaxation data. The highly flexible tips of the flaps, with the sequence Gly-Gly-Ile-Gly-Gly, are seen curling back into the protein and thereby burying many hydrophobic residues. CONCLUSIONS: This curled-in conformational change has never been previously described. Previous models of this movement, with the flaps as rigid levers, are not consistent with the experimental data. The residues that participate in this hydrophobic cluster as a result of the conformational change are highly sensitive to mutation and often contribute to drug resistance when they do change. However, several of these residues are not part of the active site cavity, and their essential role in causing drug resistance could possibly be rationalized if this conformational change actually occurs. Trapping HIV-1 protease in this inactive conformation would provide a unique opportunity for future drug design.
Source
Structure. 2000 Dec 15;8(12):1259-65.
Related Resources
Link to Article in PubMed
PubMed ID
11188690
Citation Information
Walter Robert Peter Scott and Celia A. Schiffer. "Curling of flap tips in HIV-1 protease as a mechanism for substrate entry and tolerance of drug resistance" Vol. 8 Iss. 12 (2001) ISSN: 0969-2126 (Print)
Available at: http://0-works.bepress.com.library.simmons.edu/celia_schiffer/5/