Forman Stanislav, Bobrov Alexander G, Kirillina Olga, Craig Susannah K, Abney Jennifer, Fetherston Jacqueline D, Perry Robert D
Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, Kentucky 40536-0084, USA.
Microbiology (Reading). 2006 Nov;152(Pt 11):3399-3410. doi: 10.1099/mic.0.29224-0.
Yersinia pestis biofilm formation causes massive adsorption of haemin or Congo red in vitro as well as colonization and eventual blockage of the flea proventriculus in vivo. This blockage allows effective transmission of plague from some fleas, like the oriental rat flea, to mammals. Four Hms proteins, HmsH, HmsF, HmsR and HmsS, are essential for biofilm formation, with HmsT and HmsP acting as positive and negative regulators, respectively. HmsH has a beta-barrel structure with a large periplasmic domain while HmsF possesses polysaccharide deacetylase and COG1649 domains. HmsR is a putative glycosyltransferase while HmsS has no recognized domains. In this study, specific amino acids within conserved domains or within regions of high similarity in HmsH, HmsF, HmsR and HmsS proteins were selected for site-directed mutagenesis. Some but not all of the substitutions in HmsS and within the periplasmic domain of HmsH were critical for protein function. Substitutions within the glycosyltransferase domain of HmsR and the deacetylase domain of HmsF abolished biofilm formation in Y. pestis. Surprisingly, substitution of highly conserved residues within COG1649 did not affect HmsF function.
鼠疫耶尔森菌生物膜的形成会导致其在体外大量吸附血红素或刚果红，以及在体内定殖并最终堵塞跳蚤前胃。这种堵塞使得鼠疫能够通过一些跳蚤（如印鼠客蚤）有效地传播给哺乳动物。四种Hms蛋白，即HmsH、HmsF、HmsR和HmsS，对生物膜的形成至关重要，其中HmsT和HmsP分别作为正调控因子和负调控因子发挥作用。HmsH具有一个带有大的周质结构域的β桶结构，而HmsF拥有多糖脱乙酰酶和COG1649结构域。HmsR是一种假定的糖基转移酶，而HmsS没有公认的结构域。在本研究中，选择了HmsH、HmsF、HmsR和HmsS蛋白保守结构域内或高度相似区域内的特定氨基酸进行定点诱变。HmsS和HmsH周质结构域中的一些（但不是全部）取代对蛋白质功能至关重要。HmsR糖基转移酶结构域和HmsF脱乙酰酶结构域内的取代消除了鼠疫耶尔森菌中的生物膜形成。令人惊讶的是，COG1649内高度保守残基的取代并不影响HmsF的功能。
