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Functional analysis of novel selective mutants of the reverse transcriptase of human immunodeficiency virus type 1.


J Biol Chem. 1992 Sep 15;267(26):18255-8. Unique Identifier : AIDSLINE

We have generated by site-directed mutagenesis plasmids that induce the synthesis of specific mutants of the reverse transcriptase (RT) of human immunodeficiency virus type 1 (HIV-1). These recombinant mutants of HIV-1 RT, designed on the basis of our previous studies of HIV-1 and HIV-2 RTs, were analyzed for structure-function relationship by assessing their RNA-dependent and DNA-dependent DNA polymerase as well as the ribonuclease H activities. Three groups of mutants were studied. 1) We have investigated the importance of the only two sets of highly conserved double prolines found in the sequence of HIV-1 RT. The results indicate that the conversion of either one or both prolines (at positions 225 and 226) to threonines have no significant effect on all catalytic activities of the enzyme. The mutants in which prolines 419 and 420 were individually modified to threonines exhibit full activities, whereas the double proline 419/420 mutant lost most of its RNase H activity (although the DNA polymerase function was fully retained). 2) We have deleted phenylalanine 346 from HIV-1 RT, which is absent in wild type HIV-2 RT. This mutant of HIV-1 RT lost practically all catalytic activities. 3) A mutant of HIV-1 RT in which a cysteine residue substituted for alanine 446, was found to be slightly hyperactive for both DNA polymerase and RNase H activities.

DNA Polymerases/METABOLISM Electrophoresis, Polyacrylamide Gel Escherichia coli/GENETICS Gene Expression HIV-1/*ENZYMOLOGY *Mutagenesis, Site-Directed Plasmids Ribonuclease H, Calf Thymus/METABOLISM RNA-Directed DNA Polymerase/*GENETICS/METABOLISM Support, U.S. Gov't, P.H.S. JOURNAL ARTICLE


Information in this article was accurate in December 30, 1992. The state of the art may have changed since the publication date. This material is designed to support, not replace, the relationship that exists between you and your doctor. Always discuss treatment options with a doctor who specializes in treating HIV.