Among retroviral integrases prototype foamy virus integrase displays unique biochemical activities

Abstract

Integrase enzymes of different retroviruses assemble as functional complexes with varying multimers of the protein. Retroviral integrases require a divalent metal cation to perform one-step transesterification catalysis. Tetrameric prototype foamy virus (PFV) intasomes assembled from purified integrase and viral DNA oligonucleotides were characterized for their activity in the presence of different cations. While most retroviral integrases are inactive in calcium, PFV intasomes appear to be uniquely capable of catalysis in calcium. The PFV intasomes also contrast other retroviral integrases by displaying an inverse correlation of activity with increasing manganese beginning at relatively low concentrations. The intasomes were found to be significantly more active in the presence of chloride co-ions compared to acetate. While HIV-1 integrase appears to commit to a target DNA within 20 seconds, PFV intasomes do not commit to target DNA during their reaction lifetime. Together these data highlight the unique biochemical activities of PFV integrase compared to other retroviral integrases.

Human immunodeficiency virus integration complexes are active following ordered addition of wild type integrase, viral DNA, and LEDGF/p75

“…The Sso7d mut -IN expression plasmid was modified to include a sortase cleavage site LPETGG upstream of HIV-1 IN separated by a single G residue [5,19]. Recombinant HIV-1 and LEDGF/p75 were purified as previously described [20][21][22]. Briefly, Sso7d mut -sortase cleavage site-IN and LEDGF/p75 were expressed in E. coli Rosetta (DE3) pLysS (Millipore Sigma).…”