Khan Muhammad Saleem Iqbal, Gao Xiangzheng, Liang Keying, Mei Shengsheng, Zhan Jinbiao
Department of Biochemistry, Cancer Institute of the Second Affiliated Hospital (Key Laboratory of Cancer Prevention and Intervention, China National Ministry of Education), School of Medicine, Zhejiang University, Hangzhou, China.
Front Microbiol. 2021 Aug 24;12:706700. doi: 10.3389/fmicb.2021.706700. eCollection 2021.
Phage-host interactions are likely to have the most critical aspect of phage biology. Phages are the most abundant and ubiquitous infectious acellular entities in the biosphere, where their presence remains elusive. Here, the novel lytic bacteriophage, named MSK, was isolated from the lysed culture of C (phix174 host). The genome of phage MSK was sequenced, comprising 45,053 bp with 44.8% G + C composition. In total, 73 open reading frames (ORFs) were predicted, out of which 24 showed a close homology with known functional proteins, including one tRNA-arg; however, the other 49 proteins with no proven function in the genome database were called hypothetical. Electron Microscopy and genome characterization have revealed that MSK phage has a rosette-like tail tip. There were, in total, 46 ORFs which were homologous to the Rtp genome. Among these ORFs, the tail fiber protein with a locus tag of MSK_000019 was homologous to Rtp 43 protein, which determines the host specificity. The other protein, MSK_000046, encodes lipoprotein (cor gene); that protein resembles Rtp 45, responsible for preventing adsorption during cell lysis. Thirteen MSK structural proteins were identified by SDS-PAGE analysis. Out of these, 12 were vital structural proteins, and one was a hypothetical protein. Among these, the protein terminase large (MSK_000072) subunit, which may be involved in DNA packaging and proposed packaging strategy of MSK bacteriophage genome, takes place through headful packaging using the pac-sites. Biosafety assessment of highly stable phage MSK genome analysis has revealed that the phage did not possess virulence genes, which indicates proper phage therapy. MSK phage potentially could be used to inhibit the multidrug-resistant bacteria, including AMP, TCN, and Colistin. Further, a comparative genome and lifestyle study of MSK phage confirmed the highest similarity level (87.18% ANI). These findings suggest it to be a new lytic isolated phage species. Finally, Blast and phylogenetic analysis of the large terminase subunit and tail fiber protein put it in Rtp viruses' genus of family
噬菌体与宿主的相互作用可能是噬菌体生物学最关键的方面。噬菌体是生物圈中最丰富且分布最广的传染性无细胞实体，但其存在却难以捉摸。在此，从C（噬菌体φX174宿主）的裂解培养物中分离出一种新型裂解性噬菌体，命名为MSK。对噬菌体MSK的基因组进行了测序，其基因组由45,053个碱基对组成，G + C含量为44.8%。总共预测了73个开放阅读框（ORF），其中24个与已知功能蛋白具有高度同源性，包括一个tRNA-arg；然而，基因组数据库中另外49个功能未得到证实的蛋白被称为假设蛋白。电子显微镜和基因组特征分析表明，MSK噬菌体具有玫瑰花结样的尾尖。总共有46个ORF与Rtp基因组同源。在这些ORF中，位点标签为MSK_000019的尾纤维蛋白与决定宿主特异性的Rtp 43蛋白同源。另一种蛋白MSK_000046编码脂蛋白（cor基因）；该蛋白类似于Rtp 45，负责在细胞裂解期间防止吸附。通过SDS-PAGE分析鉴定出13种MSK结构蛋白。其中，12种是重要的结构蛋白，1种是假设蛋白。其中，可能参与DNA包装的蛋白末端酶大亚基（MSK_000072），MSK噬菌体基因组的拟包装策略是通过使用pac位点的满头部包装进行。对高度稳定的噬菌体MSK基因组分析的生物安全性评估表明，该噬菌体不具有毒力基因，这表明噬菌体疗法是合适的。MSK噬菌体有可能用于抑制包括AMP、TCN和黏菌素在内的多重耐药细菌。此外，对MSK噬菌体的比较基因组和生活方式研究证实了最高相似度水平（87.18%ANI）。这些发现表明它是一种新分离的裂解性噬菌体物种。最后，对大末端酶亚基和尾纤维蛋白的Blast和系统发育分析将其归入Rtp病毒科的属中
