MECHANISM OF DNA STRAND TRANSFER-REACTIONS CATALYZED BY HIV-1 REVERSE-TRANSCRIPTASE
MECHANISM OF DNA STRAND TRANSFER-REACTIONS CATALYZED BY HIV-1 REVERSE-TRANSCRIPTASE
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DOI：
10.1126/science.1279806
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发表时间：
1992-11-13
期刊：
影响因子：
56.9
通讯作者：
BENKOVIC, SJ
中科院分区：
文献类型：
--
作者：
PELISKA, JA;BENKOVIC, SJ
在逆转录病毒逆转录过程中发生两种DNA链转移反应。第一个负链强终止DNA转移的机制已经在体外用人类免疫缺陷病毒1型逆转录酶（HIV-1 RT）和来自HIV-1基因组的模型模板-引物系统进行了研究。结果表明，HIV-1逆转录酶单独可以催化DNA链转移反应。两个动力学不同的核糖核酸酶（RNase）H活动与HIV-1 RT需要去除退火的新生DNA链的RNA片段。检测DNA的结合。RNA双链体和单链RNA在链转移过程中与HIV-1 RT的结合支持了一种模型，其中在转移事件完成之前，酶既容纳受体RNA模板又容纳新生DNA链。聚合酶活性在RNA模板的5'末端之外掺入额外的碱基，导致DNA链转移时碱基错误掺入。在逆转录病毒同源重组期间发生的这种过程可能有助于HIV-1基因组的超突变性。
Two DNA strand transfer reactions occur during retroviral reverse transcription. The mechanism of the first, minus strand strong-stop DNA, transfer has been studied in vitro with human immunodeficiency virus 1 reverse transcriptase (HIV-1 RT) and a model template-primer system derived from the HIV-1 genome. The results reveal that HIV-1 RT alone can catalyze DNA strand transfer reactions. Two kinetically distinct ribonuclease (RNase) H activities associated with HIV-1 RT are required for removal of RNA fragments annealed to the nascent DNA strand. Examination of the binding of DNA . RNA duplex and single-stranded RNA to HIV-1 RT during strand transfer supports a model where the enzyme accommodates both the acceptor RNA template and the nascent DNA strand before the transfer event is completed. The polymerase activity incorporated additional bases beyond the 5' end of the RNA template, resulting in a base misincorporation upon DNA strand transfer. Such a process occurring in vivo during retroviral homologous recombination could contribute to the hypermutability of the HIV-1 genome.