Biochemical Characterization of the HIV-1 Integrase 3'-Processing Activity and Its Inhibition by Phosphorothioate Oligonucleotides

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• 作者：Enzo Tramontano ; Paolo La Colla ; and Yung-Chi Cheng
• 刊名：Biochemistry
• 出版年：1998
• 出版时间：May 19, 1998
• 年：1998
• 卷：37
• 期：20
• 页码：7237 - 7243
• 全文大小：173K
• 年卷期：v.37,no.20(May 19, 1998)
• ISSN：1520-4995

文摘

To better understand HIV-1 integrase (IN) functions, wedetermined the kinetic parameters ofthe 3'-processing reaction. Steady-state kinetic analysisperformed using Dixon plots indicated that theconcentration of active enzyme was 10-fold lower than that calculatedby protein determination. Theturnover number was low, suggesting that IN remained bound to DNA aftercleavage. The catalyticefficiency increased 10-fold from 30 to 37 ˚C and 2-fold from 37 to42 ˚C. In enzyme assays carried outat 37 ˚C, both single- and double-stranded phosphorothioate oligosbound to IN with an efficiencycomparable to that of the phosphodiester duplex substrate. Thecompetition efficiency of single-strandedoligos was directly related to the sequence length. On the otherhand, phosphorothioate duplex U5 LTRsmodified in the plus strand were capable of both competing with thesubstrate and directly inhibiting the3'-processing activity. These results suggest that, in addition toother modes of action (inhibition ofgp120-CD4 interaction and reverse transcriptase), phosphorothioatehetero- and homopolimeric oligosalso potently inhibit the IN activity.