The core and carboxyl-terminal domains of the integrase protein of human immunodeficiency virus type 1 each contribute to nonspecific DNA binding.
The integrase protein of human immunodeficiency virus type 1 removes two nucleotides from the 3' ends of reverse-transcribed human immunodeficiency virus type 1 DNA (3' processing) and covalently inserts the processed ends into a target DNA (DNA strand transfer). Mutant integrase proteins that lack the amino-and/or carboxyl-terminal domains are incapable of catalyzing 3' processing and DNA strand transfer but are competent for an apparent reversal of the DNA strand transfer reaction (disintegration) in vitro. Here, we investigate the binding of integrase to DNA by UV cross-linking. Cross-linked complexes form with a variety of DNA substrates independent of the presence of divalent metal ion. Analysis with amino- and carboxyl-terminal deletion mutant proteins shows that residues 213 to 266 of the 288-residue protein are required for efficient cross-linking in the absence of divalent metal ion. Carboxyl-terminal deletion mutants that lack this region efficiently cross-link only to the branched disintegration DNA substrate, and this reaction is dependent on the presence of metal ion. Both the core and C-terminal domains of integrase therefore contribute to nonspecific DNA binding.
Engelman
A
A
Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892.
Hickman
A B
AB
Craigie
R
R
D001483:Base Sequence; D004254:DNA Nucleotidyltransferases / Q000378:metabolism*; D004277:DNA, Single-Stranded / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015497:HIV-1 / Q000201:enzymology*; D019426:Integrases; D008969:Molecular Sequence Data; D010777:Photochemistry; D011994:Recombinant Proteins; D017384:Sequence Deletion; D013329:Structure-Activity Relationship; D014466:Ultraviolet Rays; D016662:Virus Integration
D004277:DNA, Single-Stranded; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D011994:Recombinant Proteins; D004254:DNA Nucleotidyltransferases; D019426:Integrases