Two-step site selection for serine-integrase-mediated excision: DNA-directed integrase conformation and central dinucleotide proofreading
Two-step site selection for serine-integrase-mediated excision: DNA-directed integrase conformation and central dinucleotide proofreading
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DOI：
10.1073/pnas.0711649105
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发表时间：
2008-03-04
影响因子：
11.1
通讯作者：
Hatfull, Graham F.
中科院分区：
文献类型：
--
作者：
Ghosh, Pallavi;Bibb, Lori A.;Hatfull, Graham F.
噬菌体编码的丝氨酸整合酶是丝氨酸重组酶大家族的成员，并且催化噬菌体attP位点和细菌attB位点之间的位点特异性整合重组以形成整合的原噬菌体。原噬菌体切除涉及第二位点特异性重组事件，其中由整合产生的位点attL和attR用作再生attP和attB的底物。切除由整合酶催化，但也需要噬菌体编码的重组方向性因子（RDF）。Bxb 1重组位点attP和attB很小（< 50 bp），序列不同，并且是准对称的，它们产生不对称但彼此相似的attL-和attR-重组产物，每个都由B-和P-型半位点组成。我们在这里表明，正确的切除产物的确定是一个两步的过程，与突触前RDF依赖的步骤，对齐attL和attR在正确的方向和突触后步骤，其中的非回文中央二核苷酸赋予身份attL和attR，并防止每个重组本身。
Bacteriophage-encoded serine-integrases are members of the large family of serine-recombinases and catalyze site-specific integrative recombination between a phage attP site and a bacterial attB site to form an integrated prophage. Prophage excision involves a second site-specific recombination event, in which the sites generated by integration, attL and attR, are used as substrates to regenerate attP and attB. Excision is catalyzed by integrase but also requires a phage-encoded recombination directionality factor (RDF). The Bxb1 recombination sites, attP and attB, are small (< 50 bp), different in sequence, and quasi-symmetrical, and they give rise to attL- and attR-recombinant products that are asymmetric but similar to each other, each being composed of B- and P-type half-sites. We show here that the determination of correct excision products is a two-step process, with a presynaptic RDF-dependent step that aligns attL and attR in the correct orientation and a postsynaptic step in which the nonpalindromic central dinucleotide confers identity to attL and attR and prevents each from recombining with itself.