Institute of Genetics and Microbiology, University of Wroclaw, Wroclaw, 51-148, Poland.
Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, 117997, Russia.
Sci Rep. 2017 Nov 24;7(1):16302. doi: 10.1038/s41598-017-16411-4.
Pseudomonas phage LKA1 of the subfamily Autographivirinae encodes a tailspike protein (LKA1gp49) which binds and cleaves B-band LPS (O-specific antigen, OSA) of Pseudomonas aeruginosa PAO1. The crystal structure of LKA1gp49 catalytic domain consists of a beta-helix, an insertion domain and a C-terminal discoidin-like domain. The putative substrate binding and processing site is located on the face of the beta-helix whereas the C-terminal domain is likely involved in carbohydrates binding. NMR spectroscopy and mass spectrometry analyses of degraded LPS (OSA) fragments show an O5 serotype-specific polysaccharide lyase specificity. LKA1gp49 reduces virulence in an in vivo Galleria mellonella infection model and sensitizes P. aeruginosa to serum complement activity. This enzyme causes biofilm degradation and does not affect the activity of ciprofloxacin and gentamicin. This is the first comprehensive report on LPS-degrading lyase derived from a Pseudomonas phage. Biological properties reveal a potential towards its applications in antimicrobial design and as a microbiological or biotechnological tool.
噬菌体能编码一种尾刺蛋白（LKA1gp49），它可以结合并切割铜绿假单胞菌 PAO1 的 B 带 LPS（O 特异性抗原，OSA）。LKA1gp49 催化结构域的晶体结构由β-螺旋、插入结构域和 C 端盘绕素样结构域组成。假定的底物结合和加工位点位于β-螺旋的表面，而 C 端结构域可能参与碳水化合物的结合。对降解 LPS（OSA）片段的 NMR 光谱和质谱分析表明，该酶具有 O5 血清型特异性多糖裂解酶特异性。LKA1gp49 在体内大蜡螟感染模型中降低了毒力，并使铜绿假单胞菌对血清补体活性敏感。该酶可引起生物膜降解，且不影响环丙沙星和庆大霉素的活性。这是首次全面报道来源于铜绿假单胞菌噬菌体的 LPS 降解裂解酶。生物学特性表明其具有在抗菌设计以及作为微生物学或生物技术工具中的应用潜力。
