Fidelity of the reverse transcriptase of human immunodeficiency virus type 2.

FEBS letters (1992), Volume 306, Page 151

Abstract:

The relatively low fidelity of human immunodeficiency virus type 1 reverse transcriptase (HIV-1 RT) was implicated as a major factor that contributes to the genetic variability of the virus. Extension of mismatched 3' termini of the primer DNA was shown to be a major determinant of the infidelity of HIV-1 RT. Human immunodeficiency virus type 2 (HIV-2) also shows extensive genetic variations. Therefore, we have analyzed the fidelity of the DNA-dependent DNA polymerase activity of HIV-2 RT and compared it with those of RTs of HIV-1 and murine leukemia virus (MLV). Like other retroviral RTs, the HIV-2 RT was shown to lack a 3'----5' exonuclease activity. The ability of HIV-2 RT to extend preformed 3'-terminal A:A, A:C and A:G mispairs was examined by quantitating the amount and length of extended primers. The results demonstrate a relatively efficient mispair extension by HIV-2 RT with a specificity of A:C much greater than A:A greater than A:G. The mispair extension appears to be affected mainly by the increase of apparent Km values rather than by the change in Vmax values. The relative extension frequencies from all mispairs with HIV-1 and HIV-2 RTs was 6- to 9-fold greater than that of MLV RT, suggesting that the HIV enzymes are substantially more error-prone than MLV RT.

Polymerases:

Topics:

Reverse Transcriptase, Exonuclease Activity

Status:

new topics/pols set partial results complete validated

Results:

Polymerase Reference Property Result Context
HIV2 RT Bakhanashvili M1992 Reverse Transcriptase Activity Yes
HIV2 RT Bakhanashvili M1992 3-5' Exonuclease (proofreading) No
HIV2 RT Bakhanashvili M1992 Cloned or native Cloned in E. coli
HIV RT Bakhanashvili M1992 Reverse Transcriptase Activity Yes
HIV RT Bakhanashvili M1992 3-5' Exonuclease (proofreading) No
Klenow fragment Bakhanashvili M1992 Reverse Transcriptase Activity No
Klenow fragment Bakhanashvili M1992 3-5' Exonuclease (proofreading) Yes

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