Department of Biological Sciences, Bethel University, St. Paul, Minnesota, USA
Department of Biological and Diagnostic Sciences, University of Minnesota, Minneapolis, Minnesota, USA.
J Bacteriol. 2020 Dec 18;203(2). doi: 10.1128/JB.00544-20.
is a commensal oral organism. Harmless in the oral cavity, is an opportunistic pathogen. adheres to body surfaces using surface adhesive proteins (adhesins), which are critical to subsequent formation of biofilm communities. As in most Gram-positive bacteria, surface proteins containing the C-terminal LPXTG motif cleavage sequence are processed by sortase A (SrtA) to become covalently attached to the cell wall. To characterize the functional diversity and redundancy in the family of SrtA-processed proteins, an DL1 markerless deletion mutant library was constructed of each of the 26 putative SrtA-processed proteins. Each library member was evaluated for growth in rich medium, biofilm formation on plastic, saliva and salivary fractions, cell surface hydrophobicity (CSH), hemagglutination, and integration into an plaque biofilm community. Library members were compared to the non-SrtA-processed adhesins AbpA and AbpB. While no major growth differences in rich medium were observed, many LPXTG/A proteins impacted biofilm formation on one or more of the substrates. Several mutants showed significant differences in hemagglutination, hydrophobicity, or fitness in the plaque model. From the identification of redundant and unique functions in these and systems, functional stratification among the LPXTG/A proteins is apparent. interactions with its environment depend on the complement of cell wall proteins. A subset of these cell wall proteins requires processing by the enzyme sortase A (SrtA). The identification of SrtA-processed proteins and their functional characterization will help the community to better understand how engages with its surroundings, including other microbes, integrates into the plaque community, adheres to the tooth surface, and hematogenously disseminates to cause blood-borne infections. This study identified 26 putative SrtA-processed proteins through creation of a markerless deletion mutant library. The library was subject to functional screens that were chosen to better understand key aspects of physiology and pathogenesis.
是一种共生口腔生物。在口腔中无害，是一种机会性病原体。通过表面粘附蛋白（粘附素）粘附在身体表面，这对于随后形成生物膜群落至关重要。与大多数革兰氏阳性菌一样，含有 C 端 LPXTG 基序切割序列的表面蛋白被天冬酰胺内肽酶 A（SrtA）加工，成为共价连接到细胞壁上。为了表征 SrtA 加工蛋白家族中的功能多样性和冗余性，构建了每个 26 个假定 SrtA 加工蛋白的 DL1 无标记缺失突变体文库。评估每个文库成员在丰富培养基中的生长情况、塑料上的生物膜形成、唾液和唾液分数、细胞表面疏水性（CSH）、血凝和整合到 菌斑生物膜群落中的情况。将文库成员与非 SrtA 加工的粘附素 AbpA 和 AbpB 进行比较。虽然在丰富培养基中没有观察到主要的生长差异，但许多 LPXTG/A 蛋白在一种或多种基质上影响生物膜的形成。一些突变体在血凝、疏水性或菌斑模型中的适应性方面表现出显著差异。从这些 和 系统中冗余和独特功能的鉴定中，可以明显看出 LPXTG/A 蛋白之间的功能分层。与环境的相互作用取决于细胞壁蛋白的互补性。这些细胞壁蛋白的一部分需要酶天冬酰胺内肽酶 A（SrtA）的加工。鉴定 SrtA 加工蛋白及其功能表征将帮助科学界更好地了解 如何与周围环境相互作用，包括其他微生物，整合到菌斑群落中，附着在牙齿表面，并通过血液传播扩散以引起血液传播感染。本研究通过创建无标记缺失突变体文库鉴定了 26 种假定的 SrtA 加工蛋白。该文库进行了功能筛选，以更好地了解 生理和发病机制的关键方面。
