aeruginosaO11 PglL and antigen

aeruginosaO11 PglL and antigen.Lanes 1and2are produced by anti-pilin monoclonal antibody,lanes 3and4with anti-Pa O11 polyclonal antibody.Lane 5, purified glycosylated pilin solved by SDS-PAGE and stained by Coomassie Blue. that were synthesized by successive chemical substance and enzymatic techniques. Although FarPP provides different stereochemistry and a shorter aliphatic string compared to the organic lipid substrate considerably, the pentasaccharide was used in pilin inside our system still. We suggest that the principal roles from the lipid carrier duringO-glycosylation will be the translocation from the glycan in to the periplasm, as well as the setting from the pyrophosphate glycan and linker next to PglL. The initial characteristics of PglL get this to enzyme a promising tool for glycoengineering novel glycan-based therapeutics and vaccines. Bacterial surface area elements are comprised of, or embellished with, sugars. Among these glycosylated elements will be the type IV pili, hair-like buildings protruding in the bacterial surface, generally formed by an individual protein generically called pilin (1). Type IV pili are essential for web host cell virulence and adhesion. Furthermore, pilins areO-glycosylated in different pathogenic bacterias, includingNeisseria meningitidisandN. gonorrhoea. The glycan moieties in both types consist of brief oligosaccharides, up to three glucose residues long. Many pilin glycosylation (pgl) PEG3-O-CH2COOH genes have already been discovered inN. meningitidisencoding for glycosyltransferases and sugar-modifying enzymes that are necessary for the biosynthesis from the oligosaccharides (2). Nevertheless, the way the glycans are used in pilin provides been defined simply. Poweret al.discovered within a gene inN. meningitidiscontaining the Wzy_C PFAM domains (PF04932), a personal of enzymes that take part in O antigen biosynthesis, and which is also present in the PilO oligosaccharyltransferase (OTase) involved in pilin glycosylation inPseudomonas aeruginosa1244 (3). Inactivation of this gene, namedpglL, resulted in an increase in the electrophoretic mobility of pilin, compatible with loss of the pilin glycan. Based on this, it was suggested that PglL was responsible for the attachment of the glycan to pilin (4). Aaset al.(5) showed that mutagenesis of the PglL ortholog inN. gonorrhoea(PglO) abolished pilin glycosylation. The final demonstration that PglL is the OTase responsible for PEG3-O-CH2COOH the transfer of the glycan to pilin was provided by Faridmoayeret al.(6) who showed PglL-dependent pilin glycosylation by reconstituting the process inE. coli. Pilin glycosylation is initiated in the cytoplasm with the assembly of oligosaccharides by the sequential action of glycosyltransferases on undecaprenyl pyrophosphate (UndPP),2which is also the carrier for the synthesis of other important bacterial surface components, such as lipopolysaccharide (LPS), peptidoglycan (PG), and capsule. The lipid-linked oligosaccharide (LLO) is usually then flipped into the periplasm, where the oligosaccharide is usually attached to pilin (46). To date, only a few bacterial OTases have been explained, including PglL, PilO, andCampylobacter jejuniPglB. These OTases are integral inner membrane proteins made up of multiple membrane-spanning regions (4,7,8). PglB is usually homologous to the Stt3 component of the eukaryotic OTase complex, but not the OTases involved inO-linked protein glycosylation. PglB is responsible for theN-glycosylation of more than 30 proteins, and is thus referred PEG3-O-CH2COOH to as anN-OTase. PglB has been also functionally expressed inE. coli, and it has been shown that it can glycosylate folded proteins in anin vitroassay (7,9). In contrast, PglL and PilO are both involved inO-glycosylation, and therefore are calledO-OTases. Analogous enzymes have not PEG3-O-CH2COOH been explained in eukaryotes. Similarity between PglL and PilO is restricted to a single domain name also present in the O antigen ligases involved LPS biosynthesis. InP. aeruginosa1244, the pilin glycan is usually a single O antigen-repeating unit (10). In contrast,C. jejuniandN. meningitidisdo not possess O antigen, and instead, there is machinery dedicated to the synthesis of the LLO that will act as the sugar donor for glycosylation. In this work, we have analyzed the substrate specificity of PglL. We required advantage of the availability of well-defined UndPP-linked glycans naturally used in LPS and capsule biosynthesis, which can be produced inE. coli, to demonstrate that PglL can transfer virtually any glycan to pilinin vivo. This obtaining prompted us to hypothesize that PglL substrate specificity is located in the lipid carrier. To test this hypothesis, we established anin vitropilinO-glycosylation assay using a synthetic lipid-linked AMPK glycan obtained through successive chemical and enzymatic actions. Our results allowed us to map the region of the substrate recognized by PglL to a very short part of the molecule located at the interface between the glycan and lipid moieties. == EXPERIMENTAL PROCEDURES == Plasmids Construction and Bacteria GrowthThe details of the construction of plasmids pAMF10, expressing PglL C-His10, and pAMF15 and pAMF16 expressing C-His10-taggedN. meningitidisPilE (pilin) under IPTG or arabinose-inducible promoters,.