The orientation of mycobacteriophage Bxb1 integration is solely dependent on the central dinucleotide of attP and attB
The orientation of mycobacteriophage Bxb1 integration is solely dependent on the central dinucleotide of attP and attB
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DOI：
10.1016/s1097-2765(03)00444-1
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发表时间：
2003-11-01
期刊：
影响因子：
16
通讯作者：
Hatfull, GF
中科院分区：
文献类型：
--
作者：
Ghosh, P;Kim, AI;Hatfull, GF
分枝杆菌噬菌体 Bxb1 基因组整合到其宿主染色体中是由丝氨酸整合酶催化的，丝氨酸整合酶是位点特异性重组酶转座子解析酶家族的成员。这些酶使用协同的链交换机制，涉及双链切割和两个碱基延伸，以及通过磷酸丝氨酸键的共价蛋白质-DNA 连接。与分解酶/转化酶重组系统相比，该系统对特定突触复合体有严格的要求，在该复合体中酶的催化潜力被激活，Bxb1 整合酶对 attP 和 attB 的突触是完全混杂的，以平行和反平行排列的相同倾向排列位点。此外，Bxb1 整合酶的催化潜力在任一比对中均完全活跃。因此，attP 和 attB 中心的非回文中央二核苷酸 (5'-GT) 是 Bxb1 原噬菌体方向的唯一决定因素，两个位点中的单个碱基对替换足以消除方向控制。
Integration of the mycobacteriophage Bxb1 genome into its host chromosome is catalyzed by a serine-integrase, a member of the transposon-resolvase family of site-specific recombinases. These enzymes use a concerted mechanism of strand exchange involving double-stranded cleavages with two-base extensions, and covalent protein-DNA linkages via phosphoserine bonds. In contrast to the resolvase/invertase recombination systems-where there are strict requirements for a specific synaptic complex within which the catalytic potential of the enzyme is activated-synapsis of attP and attB by Bxb1 integrase is completely promiscuous, aligning the sites with equal proclivity in parallel and antiparallel alignments. Moreover, the catalytic potential of Bxb1 integrase is fully active in either alignment. As a consequence, the nonpalindomic central dinucleotide (5'-GT) at the center of attP and attB is the sole determinant of Bxb1 prophage orientation, and a single base pair substitution in the two sites is sufficient to eliminate orientation control.