Prevention of periodontal diseases.
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Periodontal Diseases↗
Biomedical subjects
V R Prasad
Publications and source records attributed to V R Prasad.
The effect of increased processivity on overall fidelity of human immunodeficiency virus type 1 reverse transcriptase.
We previously reported that two insertions of 15 amino acids in the beta3-beta4 hairpin loop of fingers subdomain of HIV-1(NL4-3) RT confer an increased polymerase processivity. The processivity of human immunodeficiency virus (HIV) reverse transcriptase (RT) is thought to influence the fidelity of HIV-1 RT, which tends to create errors at template sites with high termination probability. Employing the two insertion variants of HIV-1 RT (FE20 and FE103), we examined the relationship between processivity, overall fidelity and error specificity. Although the overall mutation rate was unaffected by increased processivity, one of the mutants, FE103, generated significantly fewer frameshift errors. The other mutant, FE20, generated errors at hotspots not previously observed for HIV-1 RT. Our results indicate that an increase in the polymerase processivity of HIV-1 RT does not necessarily result in a decreased mutation rate and confirm that changes in processivity alter the sequence context in which the errors are made. Furthermore, our results also reveal that the mutation frequency obtained via in vitro gap-filling reactions with wild-type HIV-1(NL4-3) RT is only 2-fold higher than that obtained via a single cycle infection assay using the same, wild-type HIV-1(NL4-3) RT sequence as part of the helper pol function [Mansky and Temin: J Virol 69:5087-5094;1995].
Base Sequence↗
Structural requirements for bacterial expression of stable, enzymatically active fusion proteins containing the human immunodeficiency virus reverse transcriptase.
A collection of variant plasmids that express the human immunodeficiency virus (HIV) reverse transcriptase as trpE fusion proteins were generated and scored for their ability to produce stable, active proteins. Trimming portions of the viral pol gene resulted in dramatic increases in yield over earlier constructs; the accumulation of high levels of enzymatically active protein in this system was increased by the retention of the trpE sequences at the amino terminus. A new in situ gel activity assay was used to demonstrate that the major induced protein, containing approximately 68 kD of viral sequences, was the active species.
Cloning, Molecular↗