Tétart F, Repoila F, Monod C, Krisch H M
Laboratoire de Microbiologie et Génétique Moléculaire CNRS, Toulouse, France.
J Mol Biol. 1996 May 24;258(5):726-31. doi: 10.1006/jmbi.1996.0281.
The adsorption specificity of T4 is determined by the tip of the gene 37 tail fibers which bind to receptors on the bacterial surface. T4 infects only Escherichia coli and closely related Shigella species, but rare host range mutants can be isolated that infect Yersinia pseudotuberculosis I, an evolutionally distant bacterium. Some of these mutations result in amino acid residue substitutions in the C-terminal portion of gene 37, but others involve unequal exchanges between a series of sequence motifs (His boxes) in the same region. The duplication or mutational alteration of this segment apparently suffices for phage adsorption to a Yersinia receptor. It is suggested that recombination between the His box sequences can generate diversity in phage host range by shuffling receptor recognition domains.
T4的吸附特异性由基因37尾丝的尖端决定，该尾丝与细菌表面的受体结合。T4仅感染大肠杆菌和密切相关的志贺氏菌属物种，但可以分离出罕见的宿主范围突变体，这些突变体可感染进化上较远的细菌——假结核耶尔森氏菌I。其中一些突变导致基因37 C末端部分的氨基酸残基替换，但其他突变涉及同一区域一系列序列基序（组氨酸盒）之间的不等交换。该片段的重复或突变改变显然足以使噬菌体吸附到耶尔森氏菌受体上。有人提出，组氨酸盒序列之间的重组可通过改组受体识别域来产生噬菌体宿主范围的多样性。
