title: Substrate shape determines specificity of recognition for HIV-1 protease: analysis of crystal structures of six substrate complexes.
abstract: The homodimeric HIV-1 protease is the target of some of the most effective antiviral AIDS therapy, as it facilitates viral maturation by cleaving ten asymmetric and nonhomologous sequences in the Gag and Pol polyproteins. Since the specificity of this enzyme is not easily determined from the sequences of these cleavage sites alone, we solved the crystal structures of complexes of an inactive variant (D25N) of HIV-1 protease with six peptides that correspond to the natural substrate cleavage sites. When the protease binds to its substrate and buries nearly 1000 A2 of surface area, the symmetry of the protease is broken, yet most internal hydrogen bonds and waters are conserved. However, no substrate side chain hydrogen bond is conserved. Specificity of HIV-1 protease appears to be determined by an asymmetric shape rather than a particular amino acid sequence.
authors: Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester 01655, USA.
authors: Moses
authors: M
authors: Prabu-Jeyabalan
authors: Ellen
authors: E
authors: Nalivaika
authors: Celia A
authors: CA
authors: Schiffer
mesh_terms: D001665:Binding Sites; D018360:Crystallography, X-Ray; D015683:Gene Products, gag / Q000737:chemistry / Q000378:metabolism; D016333:HIV Protease / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D006801:Humans; D006860:Hydrogen Bonding; D008024:Ligands; D008958:Models, Molecular; D015394:Molecular Structure; D010455:Peptides / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity; D014867:Water / Q000737:chemistry
chemical_list: D015683:Gene Products, gag; D008024:Ligands; D010455:Peptides; D014867:Water; D016333:HIV Protease