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A possible role for cysteine residues in the fidelity of DNA synthesis exhibited by the reverse transcriptases of human immunodeficiency viruses type 1 and type 2
Author(s) -
Bakhanashvili Mary,
Hizi Am
Publication year - 1992
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(92)80640-3
Subject(s) - cysteine , dna , mutant , chemistry , dna synthesis , wild type , biochemistry , enzyme , microbiology and biotechnology , biology , gene
HIV reverse transcriptases (RTs) have few cysteine residues relative to other RTs and retain their DNA polymerization functions following chemical modification by thiol‐specific reagents. The functional role of the cysteines in the fidelity of the DNA‐dependent DNA synthesis of HIV RTs has been addressed by chemical modification of the wild‐type enzymes in combination with the analysis of an enzymatically active mutant HIV‐1 RT in which all cysteines were modified to serines. We have observed an increase in 3′‐terminal mispair extension efficiency exhibited by chemically modified HIV‐1 and HIV‐2 RTs. The possible involvement of cysteine residues was further substantiated using the cysteine‐free mutant HIV‐1 RT that displays an increased efficiency of mispair extension. These results provide evidence for a possible role of cysteine residues in the fidelity of DNA synthesis catalyzed by HIV RTs.