1B9F

MOBILITY OF AN HIV-1 INTEGRASE ACTIVE SITE LOOP IS CORRELATED WITH CATALYTIC ACTIVITY

Summary for 1B9F

• Entry DOI: 10.2210/pdb1b9f/pdb
• Descriptor: PROTEIN (INTEGRASE), CACODYLATE ION, SULFATE ION, ... (4 entities in total)
• Functional Keywords: dna integration, transferase
• Biological source: Human immunodeficiency virus type 1 (CLONE 12)
• Cellular location: Gag-Pol polyprotein: Host cell membrane; Lipid-anchor . Matrix protein p17: Virion membrane; Lipid- anchor . Capsid protein p24: Virion . Nucleocapsid protein p7: Virion . Reverse transcriptase/ribonuclease H: Virion . Integrase: Virion : P12497
• Total number of polymer chains: 1
• Total formula weight: 18310.57

Authors

Greenwald, J.,Le, V.,Butler, S.L.,Bushman, F.D.,Choe, S. (deposition date: 1999-02-11, release date: 1999-07-19, Last modification date: 2023-12-27)

Primary citation

Greenwald, J.,Le, V.,Butler, S.L.,Bushman, F.D.,Choe, S.
The mobility of an HIV-1 integrase active site loop is correlated with catalytic activity.
Biochemistry, 38:8892-8898, 1999

PubMed Abstract: Replication of HIV-1 requires the covalent integration of the viral cDNA into the host chromosomal DNA directed by the virus-encoded integrase protein. Here we explore the importance of a protein surface loop near the integrase active site using protein engineering and X-ray crystallography. We have redetermined the structure of the integrase catalytic domain (residues 50-212) using an independent phase set at 1.7 A resolution. The structure extends helix alpha4 on its N-terminal side (residues 149-154), thus defining the position of the three conserved active site residues. Evident in this and in previous structures is a conformationally flexible loop composed of residues 141-148. To probe the role of flexibility in this loop, we replaced Gly 140 and Gly 149, residues that appear to act as conformational hinges, with Ala residues. X-ray structures of the catalytic domain mutants G149A and G140A/G149A show further rigidity of alpha4 and the adjoining loop. Activity assays in vitro revealed that these mutants are impaired in catalysis. The DNA binding affinity, however, is minimally affected by these mutants as assayed by UV cross-linking. We propose that the conformational flexibility of this active site loop is important for a postbinding catalytic step.

PubMed: 10413462
DOI: 10.1021/bi9907173

Experimental method

X-RAY DIFFRACTION (1.7 Å)