Comparative enzymatic study of HIV-1 reverse transcriptase resistant to 2',3'-dideoxynucleotide analogs using the single-nucleotide incorporation assay.

Abstract:

Employing the single-nucleotide incorporation assay using a ...
Employing the single-nucleotide incorporation assay using a heteropolymeric RNA template and DNA primers, we defined enzymatic profiles of recombinant human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) containing a set of five mutations [A62V, V75I, F77L, F116Y, and Q151M] which confers resistance to multiple 2',3'-dideoxynucleosides (ddNs) on HIV-1. RTs containing other drug-resistance-associated mutations were also examined. The K(m) for dNTPs, the kcat, and the kcat/ K(m) ratios of mutant RTs were all comparable to those of wild-type RT (RTwt). The processive primer extension activity of mutant RTs was also comparable to that of RTwt as examined in the presence of saturating concentrations of dNTPs and heparin. Determination of the Ki values toward 5'-triphosphates (TP) of various ddNs [3'-azido-2',3'-dideoxythymidine (AZT), 2',3'-didehydro-2',3'-dideoxythymidine (D4T), 2',3'-dideoxycytidine (ddC), (-)-beta-L-2',3'-dideoxy-3'-thiacytidine (3TC), (-)-beta-L-2',3'-dideoxy-5-fluorocytidine (FddC), 2',3'-dideoxyadenosine (ddA), and 2'-beta-fluoro-2',3'-dideoxyadenosine (FddA)] and 9-(2-phosphonylmethoxyethyl)adenine diphosphate (PMEApp) revealed that RTA62V/V75I/F77L/F116Y/Q151M was insensitive to ddATP, AZTTP, D4TTP, FddATP, and ddCTP, but was sensitive to PMEApp, 3TCTP, and FddCTP. RTK65R was less sensitive to ddATP, FddATP, PMEApp, ddCTP, and 3TCTP, while RTM184V was less sensitive only to 3TCTP and ddCTP. The determination of Ki(ddNTP)/K(m)(dNTP) ratios showed that AZTTP, D4TTP, and ddCTP are, as substrates, as efficient for RTwt as their corresponding dNTPs, that ddATP, PMEApp, and 3TCTP are moderately efficient substrates for RTwt, and that FddATP is the least efficient substrate among ddNTPs examined. The observed cross-resistance of HIV-1 RT to various ddNTPs should reflect the alteration of RT's substrate recognition and should provide insights into the molecular mechanism of RT discrimination of ddNTPs from natural substrates.

Polymerases:

Topics:

Mutational Analysis, Health/Disease, Kinetic Parameters, Nucleotide Analogs / Template Lesions, Nucleotide Incorporation

Status:

new topics/pols set partial results complete validated

Results:

No results available for this paper.

Entry validated by:

Using Polbase tables:

Sorting:

Tables may be sorted by clicking on any of the column titles. A second click reverses the sort order. <Ctrl> + click on the column titles to sort by more than one column (e.g. family then name).

Filtering:

It is also possible to filter the table by typing into the search box above the table. This will instantly hide lines from the table that do not contain your search text.