State Key Laboratory of Virology, Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, China.
Antimicrob Agents Chemother. 2012 Oct;56(10):5031-9. doi: 10.1128/AAC.00891-12. Epub 2012 Jul 16.
As a potential antimicrobial, the bacteriophage lysin PlyG has been reported to specifically recognize Bacillus anthracis vegetative cells only and to kill B. anthracis vegetative cells and its germinating spores. However, how PlyG interacts with B. anthracis spores remains unclear. Herein, a 60-amino-acid domain in PlyG (residues 106 to 165), located mainly in the previously identified catalytic domain, was found able to specifically recognize B. anthracis spores but not vegetative cells. The exosporium of the spores was found to be the most probable binding target of this domain. This is the first time that a lysin for spore-forming bacteria has been found to have separate domains to recognize spores and vegetative cells, which might help in understanding the coevolution of phages with spore-forming bacteria. Besides providing new biomarkers for developing better assays for identifying B. anthracis spores, the newly found domain may be helpful in developing PlyG as a preventive antibiotic to reduce the threat of anthrax in suspected exposures to B. anthracis spores.
作为一种有潜力的抗菌物质，噬菌体溶菌酶 PlyG 已被报道仅能特异性识别炭疽杆菌营养细胞，并能杀死炭疽杆菌营养细胞及其发芽孢子。然而，PlyG 如何与炭疽杆菌孢子相互作用尚不清楚。本文发现，PlyG 中一个 60 个氨基酸的结构域（残基 106 到 165），主要位于先前鉴定的催化结构域内，能够特异性识别炭疽杆菌孢子但不能识别营养细胞。发现该结构域最有可能的结合靶标是孢子的外被。这是首次发现一种产芽孢细菌的溶菌酶具有分别识别孢子和营养细胞的结构域，这可能有助于理解噬菌体与产芽孢细菌的共同进化。除了为开发更好的炭疽杆菌孢子鉴定方法提供新的生物标志物外，新发现的结构域可能有助于将 PlyG 开发为预防性抗生素，以减少对炭疽杆菌孢子疑似暴露的炭疽威胁。
