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Enzymatic analysis of two HIV-1 reverse transcriptase mutants with mutations in carboxyl-terminal amino acid residues conserved among retroviral ribonucleases H

Title data

Volkmann, Silke ; Wöhrl, Birgitta Maria ; Tisdale, Margaret ; Moelling, Karin:
Enzymatic analysis of two HIV-1 reverse transcriptase mutants with mutations in carboxyl-terminal amino acid residues conserved among retroviral ribonucleases H.
In: The Journal of Biological Chemistry. Vol. 268 (1993) Issue 4 . - pp. 2674-2683.
ISSN 1083-351X

Official URL: Volltext

Abstract in another language

The reverse transcriptase (RT) of HIV-1 has been mutagenized within the carboxyl-terminal domain which harbors the RNase H. Two amino acids highly conserved among all 14 known RT sequences but not in the bacterial RNase H have been mutagenized resulting in the mutant proteins N494D and Q475E. They were expressed as recombinant proteins, purified, and analyzed for their in vitro properties in comparison to the p66 homodimeric wild-type and a previously described H539N mutant. The N494D mutant closely resembles the wild-type RNase H, exhibits an endonuclease activity and a processive RNase H activity, gives rise to small RNA hydrolysis products, and acts in concert with the RT. The Q475E mutant is more defective and resembles the H539N mutant, exhibits a retarded endonuclease activity and an impaired 3'-->5' processive RNA cleavage activity, gives rise to predominantly larger RNA hydrolysis products, is less processive in the presence of competitor substrate, and is defective in its ability to hydrolyze the polypurine tract and homopolymeric hybrids. Short homopolymeric stretches cause a pausing of the RT of wild-type and mutants which results in a coordinated action of the RNase H. Pausing of the RT correlates with RNase H cleavages about 20 nucleotides behind the point of synthesis. The defects of the mutant enzymes can be interpreted on the basis of the known crystallography data.

Further data

Item Type: Article in a journal
Refereed: Yes
Institutions of the University: Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Biopolymers
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Chemistry > Chair Biopolymers > Lehrstuhl Biopolymere - Apl. Prof. Dr. Birgitta Wöhrl
Result of work at the UBT: No
DDC Subjects: 500 Science > 540 Chemistry
500 Science > 570 Life sciences, biology
Date Deposited: 20 May 2019 08:12
Last Modified: 20 May 2019 08:12
URI: https://eref.uni-bayreuth.de/id/eprint/49005