Genome plasticity in the distal tail fiber locus of the T-even bacteriophage:: Recombination between conserved motifs swaps adhesin specificity
Genome plasticity in the distal tail fiber locus of the T-even bacteriophage:: Recombination between conserved motifs swaps adhesin specificity
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DOI：
10.1006/jmbi.1998.2047
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发表时间：
1998-09-25
影响因子：
5.6
通讯作者：
Krisch, HM
中科院分区：
文献类型：
--
作者：
Tètart, F;Desplats, C;Krisch, HM
T-偶数噬菌体的吸附专一性由长尾纤维顶端附近的蛋白质序列决定。这些粘附素序列在它们的序列和细菌受体的特异性上都是高度可变的。尾部纤维粘附素结构域位于T-偶数型密切相关噬菌体中的不同基因中。在噬菌体T4中，粘附素序列是由大尾纤维基因(基因37)的C末端结构域编码的，而在T2噬菌体中，粘附素是一个独立的基因产物(基因38)，它与T2尾纤维的末端结合。对噬菌体T6和AC3序列的分析揭示了该基因座的其他变异形式。尾部纤维宿主特异性决定因素是可以交换的，尽管不同的基因座只有有限的同源性。嵌合纤维可以通过纤维基因结构部分内的小同源之间或粘附素结构域的保守基序之间的交叉而产生。例如，T2粘附素决定因素被富含G的DNA基序包围，涉及这些序列的交换可以取代特异性决定因素。远端尾部纤维基因座的这些特征在遗传上将它们的不同形式联系在一起，并可以调节不同宿主范围决定因素的获得，包括那些允许其跨越物种边界并感染分类上遥远的宿主的决定因素。(C)1998年学术出版社。
The adsorption specificity of the T-even phages is determined by the protein sequence near the tip of the long tail fibers. These adhesin sequences are highly variable in both their sequence and specificity for bacterial receptors. The tail fiber adhesin domains are located in different genes in closely related phages of the T-even type. In phage T4, the adhesin sequence is encoded by the C-terminal domain of the large tail fiber gene (gene 37), but in T2, the adhesin is a separate gene product (gene 38) that binds to the tip of T2 tail fibers. Analysis of phage T6 and Ac3 sequences reveals additional variant forms of this locus. The tail fiber host specificity determinants can be exchanged, although the different loci have only limited homology. Chimeric fibers can be created by crossovers either between small homologies within the structural part of the fiber gene or in conserved motifs of the adhesin domain. For example, the T2 adhesin determinants are flanked by G-rich DNA motifs and exchanges involving these sequences can replace the specificity determinants. These features of the distal tail fiber loci genetically link their different forms and can mediate acquisition of diverse host range determinants, including those that allow it to cross species boundaries and infect taxonomically distant hosts. (C) 1998 Academic Press.