Methylphosphonodiester substitution near the conserved CA dinucleotide in the HIV LTR alters both extent of 3′-Processing and choice of nucleophile by HIV-1 integrase
Year: 1994
Type: article
Abstract: We present evidence suggesting that the 3'-processing activity of HIV-1 integrase is dramatically affected by electrostatic and/or steric perturbations 3' to the conserved CA dinucleotide. When the phosphodiester bond 3' to the scissile phosphodiester is replaced by a methylphosphonodiester linkage, 3'-processing decreases by two orders of magnitude. This block of cleavage can be somewhat overcome by increasing the pH of the reaction. Labeling of the substrates at the 3'-end revealed blockage of water and glycerol, but stimulation of the viral DNA 3'-hydroxyl, acting as the nucleophile with the methylphosphonodiester substrate. Interestingly, a circular trinucleotide was formed using the phosphodiester and methylphosphonodiester substrates when the terminal nucleotide was 3'-deoxyadenosine but not 2'-deoxyadenosine. Mutagenesis of the enzyme active site has previously been shown to alter the choice of nucleophile in the 3'-processing reaction. Taken together, the results in this study suggest that 'mutagenesis' of the DNA backbone can also alter the choice of nucleophile.
Source: Nucleic Acids Research
Authors: Abhijit Mazumder, Malini Gupta, Yves Pommier
Institutions: National Institutes of Health, National Cancer Institute
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2020589373