中文摘要：噬菌体是地球上最丰富多样的生物实体，具有严格的宿主特异性，这在很大程度上由吸附作用决定，但对噬菌体宿主特异性背后的机制仍然知之甚少。本研究检测了大肠杆菌受体之一的外膜蛋白C (OmpC)和T4噬菌体的长尾纤维之间的相互作用。尽管大肠杆菌K-12和O157的OmpC同源性高达94%，但本研究中T4噬菌体采用K-12菌株而非O157菌株的OmpC进行吸附。研究确定了在K-12 OmpC环1和环5共存时，环4中的氨基酸P177和F182对T4噬菌体吸附至关重要。对能够吸附OmpC突变体的噬菌体突变体分析表明，存在于T4长尾纤维远端末端（DT）区域的gp37蛋白的937和942位的氨基在吸附中起重要作用。此外，还对DT区域进行了人工修饰，创建了一个T4噬菌体突变体文库，并分离、鉴定了多个能够吸附O157菌株OmpC或K-12菌株脂多糖的噬菌体突变体。这些结果揭示了gp37和OmpC介导的噬菌体宿主特异性的机制，并可能有助于通过人工修饰T4噬菌体的DT区开发噬菌体治疗。
  重点：了解噬菌体的宿主特异性将有助于噬菌体治疗的发展。大肠杆菌受体之一的外膜蛋白C（OmpC）与T4噬菌体长尾纤维远端末端（DT）区域的gp37蛋白之间的相互作用在很大程度上决定了它们的宿主特异性。本文阐明了gp37和OmpC之间相互作用的重要氨基酸残基，表明结合界面上两种蛋白质的形状在它们的相互作用中起着重要作用，这可能是由两种结合伙伴的多个残基介导的。此外，利用突变T4噬菌体库，在DT区域进行人工修饰，成功分离出多个能够吸附于多种大肠杆菌受体的噬菌体突变体，为改变宿主特异性提供了基础。
外文摘要：Bacteriophages are the most abundant and diverse biological entities on Earth. Phages exhibit strict host specificity that is largely conferred by adsorption. However, the mechanism underlying this phage host specificity remains poorly understood. In this study, we examined the interaction between outer membrane protein C (OmpC), one of the Escherichia coli receptors, and the long tail fibers of bacteriophage T4. T4 phage uses OmpC of the K-12 strain, but not of the O157 strain, for adsorption, even though OmpCs from the two E. coli strains share 94% homology. We identified amino acids P177 and F182 in loop 4 of the K-12 OmpC as essential for T4 phage adsorption in the copresence of loops 1 and 5. Analyses of phage mutants capable of adsorbing to OmpC mutants demonstrated that amino adds at positions 937 and 942 of the gp37 protein, which is present in the distal tip (DT) region of the T4 long tail fibers, play an important role in adsorption. Furthermore, we created a T4 phage mutant library with artificial modifications in the DT region and isolated and characterized multiple phage mutants capable of adsorbing to OmpC of the O157 strain or lipopolysaccharide of the K-12 strain. These results shed light on the mechanism underlying the phage host specificity mediated by gp37 and OmpC and may be useful in the development of phage therapy via artificial modifications of the DT region of T4 phage.
   IMPORTANCE Understanding the host specificity of phages will lead to the development of phage therapy. The interaction between outer membrane protein C (OmpC), one of the Escherichia coli receptors, and the gp37 protein present in the distal tip (DT) region of the long tail fibers of T4 bacteriophages largely determines their host specificity. Here, we elucidated the amino acid residues important for the interaction between gp37 and OmpC. This result suggests that the shapes of both proteins at the binding interface play important roles in their interactions, which are likely mediated by multiple residues of both binding partners. Additionally, we successfully isolated multiple phage mutants capable of adsorbing to a variety of E. coli receptors using a mutant T4 phage library with artificial modifications in the DT region, providing a foundation for the alteration of the host specificity.
外文关键词：Escherichia coli；bacteriophage therapy；bacteriophages
作者：Suga, A；Kawaguchi, M；Yonesaki, T；Otsuka, Y
作者单位：Saitama Univ；Osaka Univ
期刊名称：APPLIED AND ENVIRONMENTAL MICROBIOLOGY
期刊影响因子：4.016
出版年份：2021
出版刊次：13
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