Mazumder A, Engelman A, Craigie R, Fesen M, Pommier Y
Laboratory of Molecular Pharmacology, NCI, Rockville, MD 20892.
Nucleic Acids Res. 1994 Mar 25;22(6):1037-43. doi: 10.1093/nar/22.6.1037.
We report the activities of HIV integrase protein on a novel DNA substrate, consisting of a pair of gapped duplex molecules. Integrase catalyzed an intermolecular disintegration reaction that requires positioning of a pair of the gapped duplexes in a configuration that resembles the intgration intermediate. However, the major reaction resulted from an intramolecular reaction involving a single gapped duplex, giving rise to a hairpin. Surprisingly, a deletion mutant of integrase that lacks both the amino and carboxyl terminal regions still catalyzed the intermolecular disintegration reaction, but supported only a very low level of the intramolecular reaction. The central core region of integrase is therefore sufficient to both bind the gapped duplex DNA and juxtapose a pair of such molecules through protein-protein interactions. We suggest that the branched DNA structures of the previously reported disintegration substrate, and the intermolecular disintegration substrate described here, assist in stabilizing protein-protein interactions that otherwise require the amino and carboxy terminal regions of integrase.
我们报道了HIV整合酶蛋白在一种新型DNA底物上的活性，该底物由一对有缺口的双链分子组成。整合酶催化了一种分子间解体反应，此反应需要将一对有缺口的双链以类似于整合中间体的构型排列。然而，主要反应来自涉及单个有缺口双链的分子内反应，产生了一个发夹结构。令人惊讶的是，一种缺失氨基和羧基末端区域的整合酶缺失突变体仍能催化分子间解体反应，但仅支持非常低水平的分子内反应。因此，整合酶的中央核心区域足以结合有缺口的双链DNA，并通过蛋白质-蛋白质相互作用使一对这样的分子并列。我们认为，先前报道的解体底物的分支DNA结构以及此处描述的分子间解体底物，有助于稳定蛋白质-蛋白质相互作用，否则这种相互作用需要整合酶的氨基和羧基末端区域。
