title: The HIV-1 integrase monomer induces a specific interaction with LTR DNA for concerted integration.
abstract: The assembly mechanism for the human immunodeficiency virus type 1 (HIV) synaptic complex (SC) capable of concerted integration is unknown. Molecular and structural studies have established that the HIV SC and prototype foamy virus (PFV) intasome contain a tetramer of integrase (IN) that catalyzes concerted integration. HIV IN purified in the presence of 1 mM EDTA and 10 mM MgSO(4) was predominately a monomer. IN efficiently promoted concerted integration of micromolar concentrations of 3'-OH recessed and blunt-ended U5 long terminal repeat (LTR) oligonucleotide (ODN) substrates (19-42 bp) into circular target DNA. Varying HIV IN to U5 DNA showed that an IN dimer:DNA end molar ratio of 1 was optimal for concerted integration. Integration activities decreased with an increasing length of the ODN, starting from the recessed 18/20 or 19/21 bp set to the 31/33 and 40/42 bp set. Under these conditions, the average fidelity for the HIV 5 bp host site duplication with recessed and blunt-ended substrates was 56%. Modifications of U5 LTR sequences beyond 21 bp from the terminus on longer DNA (1.6 kb) did not alter the ~32 bp DNaseI protective footprint, suggesting viral sequences beyond 21 bp were not essential for IN binding. The results suggest IN binds differentially to an 18/20 bp than to a 40/42 bp ODN substrate for concerted integration. The HIV IN monomer may be a suitable candidate for attempting crystallization of an IN-DNA complex in the absence or presence of strand transfer inhibitors.
authors: Institute for Molecular Virology, Saint Louis University Health Sciences Center, Saint Louis, Missouri 63104, United States.
authors: Krishan K
authors: KK
authors: Pandey
authors: Sibes
authors: S
authors: Bera
authors: Duane P
authors: DP
authors: Grandgenett
mesh_terms: D001483:Base Sequence; D019427:HIV Integrase / Q000737:chemistry* / Q000235:genetics / Q000502:physiology*; D016325:HIV Long Terminal Repeat / Q000235:genetics / Q000502:physiology*; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D020836:Protein Structure, Quaternary; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity; D016662:Virus Integration / Q000235:genetics / Q000502:physiology*
chemical_list: D011994:Recombinant Proteins; D019427:HIV Integrase; C514801:p31 integrase protein, Human immunodeficiency virus 1