title: Sequence-independent processing site of the C-terminal domain (CTD) influences maturation of the RgpB protease from Porphyromonas gingivalis.
abstract: The Gram-negative periodontal pathogen Porphyromonas gingivalis produces a family of outer membrane-anchored proteases, the gingipains, shown to play an essential role in virulence of the organism. The C-terminal domain (CTD) of gingipains and other secreted proteins is known to be the targeting signal for maturation and translocation of the protein through the outer membrane. The CTD is subsequently cleaved during the secretion process. Multiple alignment of various CTDs failed to define a consensus sequence at the putative CTD processing site. Using mutagenesis, we were able to show that cleavage at the site is not dependent on a specific residue and that recognition of the site is independent of local sequence. Interestingly, length of the junction between the CTD and adjacent Ig-like subdomain has a critical influence on post-translational glycan modification of the protein, whereby insertion of additional residues immediately N-terminal to the cleavage site results in failure of glycan modification and release of soluble protease into the culture medium. Various hypotheses are presented to explain these phenomena. Knowledge of the role CTDs play in maturation of gingipains has broader application for understanding maturation of CTD homologues expressed by bacteria of the Bacteriodetes phylum.
authors.affiliation: Institute of Dental Research, Westmead Centre for Oral Health and Westmead Millennium Institute, Sydney, NSW, Australia.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Zhou
authors.forename: Jin-Long
authors.initials: JL
authors.lastname: Gao
authors.forename: Neil
authors.initials: N
authors.lastname: Hunter
authors.forename: Jan
authors.initials: J
authors.lastname: Potempa
authors.forename: Ky-Anh
authors.initials: KA
authors.lastname: Nguyen
mesh_terms: D018829:Adhesins, Bacterial / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D004252:DNA Mutational Analysis; D000080867:Gingipain Cysteine Endopeptidases; D006031:Glycosylation; D008969:Molecular Sequence Data; D016966:Porphyromonas gingivalis / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D016415:Sequence Alignment
chemical_list: D018829:Adhesins, Bacterial; D000080867:Gingipain Cysteine Endopeptidases; D003546:Cysteine Endopeptidases