Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou 310058, PR China.
Microbiology (Reading). 2013 Aug;159(Pt 8):1597-1605. doi: 10.1099/mic.0.067611-0. Epub 2013 Jun 19.
The holin-endolysin system is used by double-stranded DNA phages to lyse their bacterial hosts at the terminal stage of the phage reproduction cycle. Endolysins are proteins with one of several muralytic activities able to digest the bacterial cell wall for phage progeny release. However, the functions of thermophilic bacteriophage endolysin in host lysis have not been extensively investigated. In this study, the roles of the endolysin of a thermophilic bacteriophage, GVE2, from a deep-sea hydrothermal vent, which could infect Geobacillus sp. E263 at high temperatures, were characterized. The results showed that GVE2 could lead to lysis of host cells. The confocal microscopy data showed that GFP-endolysin aggregated in GVE2-infected Geobacillus sp. E263 cells, showing the involvement of endolysin in the lysis process at high temperatures. The results revealed that the GVE2 endolysin and holin interacted directly. It was found that the endolysin could interact with the host protein ABC transporter, suggesting that host proteins might participate in the regulation of the lysis process. Therefore, our study presents a novel insight into the mechanism of the lysis process of a thermophilic bacterium by its phage at high temperatures, which should be helpful in revealing the roles of thermophilic bacteriophages in the biosphere of deep-sea hydrothermal vents.
溶原酶-内切酶系统被双链 DNA 噬菌体用于在噬菌体繁殖周期的终末阶段裂解其细菌宿主。内切酶是具有几种溶壁活性之一的蛋白质，能够消化细菌细胞壁以释放噬菌体后代。然而，嗜热噬菌体内切酶在宿主裂解中的功能尚未得到广泛研究。在这项研究中，我们对一种来自深海热液喷口的嗜热噬菌体 GVE2 的内切酶的作用进行了表征，该噬菌体可以在高温下感染 Geobacillus sp. E263。结果表明，GVE2 可以导致宿主细胞裂解。共聚焦显微镜数据显示，GFP-内切酶在 GVE2 感染的 Geobacillus sp. E263 细胞中聚集，表明内切酶参与了高温下的裂解过程。结果表明，GVE2 内切酶和 holin 直接相互作用。发现内切酶可以与宿主蛋白 ABC 转运蛋白相互作用，这表明宿主蛋白可能参与了裂解过程的调节。因此，我们的研究为高温下噬菌体裂解嗜热细菌的机制提供了新的见解，这有助于揭示深海热液喷口环境中嗜热噬菌体的作用。
