Lasica AM, Ksiazek M, Madej M, Potempa J. The image was produced by ESPript 3.01 (49). Sequence alignment was performed using Clustal Omega (50). Download FIG?S2B2, TIF file, 0.5 MB. Copyright ? 2021 Madej et al. This content is usually distributed under the terms of the Creative Commons Attribution 4.0 International license. FIG?S2C. Specificity of PorZ from was titrated with increasing concentrations of purified A-LPS from W83. The results are presented JNJ-31020028 as means the SD from three experiments. Download FIG?S2C, TIF file, 0.7 MB. JNJ-31020028 Copyright ? 2021 Madej JNJ-31020028 et al. This content is usually distributed under the terms of the Creative Commons Attribution 4.0 International license. TABLE?S1. strains used in this study. Download Table?S1, DOCX file, 0.02 MB. Copyright ? 2021 Madej et al. This content is usually distributed under the terms of the Creative Commons Attribution 4.0 International license. TABLE?S2. strains and plasmids used in this study. Download Table?S2, DOCX file, 0.02 MB. Copyright ? 2021 Madej et al. This content is usually distributed under the terms of the Creative Commons Attribution 4.0 International license. TABLE?S3. Primers used in this study. Download Table?S3, DOCX file, 0.02 MB. Copyright ? 2021 Madej et al. This content is usually distributed under the terms of the Creative Commons Attribution 4.0 International license. ABSTRACT Cargo proteins of the type IX secretion system (T9SS) in human pathogens from the Bacteroidetes phylum invariably possess a conserved C-terminal domain name (CTD) that functions as a signal for outer membrane (OM) translocation. In is usually a major periodontal pathogen that resides in the human gingival crevice. As an asaccharolytic organism, it acquires nutrients in the form of peptides from proteins localized in the gingival crevicular fluid (7, 8). In contrast to the majority of Gram-negative bacteria, produces two different types of lipopolysaccharide (LPS) molecules (9,C11). Both contain the conserved lipid A endotoxin and a core oligosaccharide, but they differ in the highly variable polysaccharide (PS), called the O-antigen, attached to the core. The PS of the more common O-LPS (O-PS) consists of repeating models of a single tetrasaccharide, whereas anionic polysaccharide (A-LPS) consists of a phosphorylated branched mannan (9,C11) (Fig.?1). Open in a separate windows FIG?1 Anionic lipopolysaccharide (A-LPS) of is shown. A-LPS consists of the A-type anionic distal polysaccharide (APS), the core oligosaccharide, and the endotoxin or lipid A. APS is made of an -d-mannose (MAN) backbone, which has side chains of one or two MANs. One of these side chains contains the branched phosphomannan element recognized by PorZ (orange background). The core oligosaccharide spans a linear chain of MANs that constitute the inner core. One of the monomers is usually linked to the mannose backbone of APS (orange dashed line). The two central MANs of MDK the inner core are linked to phosphoethanolamine (PEA). The inner core chain of MANs is usually linked to the outer core through a glycerol molecule (GRO). The latter is usually linked to -d-allosamine (ALL) and to a 3-deoxy-d–manno-oct-2-ulopyranosonic acid (KDO) via a phosphate. Monomer KDO is usually linked (orange line) to a -d-glucosamine (GLCN) from lipid A. The latter is usually linked to a -d-glucosamine (GLCN) and gives rise to the disaccharide bone structure of lipid A, which carries a phosphate and the lipids. Phosphate groups are depicted as red circles. The mutant lacks an O-antigen polymerase and its A-LPS is composed of the single APS unit. The mutant, in turn, affects an -1,3-mannosyltransferase, which leads to a truncated core that lacks -(13)-linked mannoses and is devoid of APS (39). To thrive in JNJ-31020028 the inflammatory environment of its colonization site (12), secretes an array of proteinaceous virulence factors. These proteins, including the major extracellular proteolytic brokers RgpA, RgpB, and Kgp (collectively called gingipains) (13, 14), possess an N-terminal signal peptide that directs their translocation through the inner membrane (IM) into the periplasmic space via the system. In addition, they have a conserved C-terminal domain name (CTD) with an Ig-like fold involved in targeted transport across the outer membrane (OM) via the type IX secretion system (T9SS) (15,C19). Despite participating only in OM translocation, the T9SS spans both the IM and the OM (20,C22). Its protein components reside around the IM (PorL and PorM) (23, 24) or in the periplasm (PorN, PorK, PorW, and PorE) (25,C27); constitute the OM translocon.