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Phylum‐wide general protein O ‐glycosylation system of the B acteroidetes
Author(s) -
Coyne Michael J.,
Fletcher C. Mark,
ChatzidakiLivanis Maria,
Posch Gerald,
Schaffer Christina,
Comstock Laurie E.
Publication year - 2013
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/mmi.12220
Subject(s) - biology , glycan , glycosylation , glycoprotein , bacteroides fragilis , bacteroidetes , biochemistry , n linked glycosylation , peptide sequence , microbiology and biotechnology , gene , 16s ribosomal rna , antibiotics
Summary The human gut symbiont B acteroides fragilis has a general protein O ‐glycosylation system in which numerous extracytoplasmic proteins are glycosylated at a three amino acid motif. In B . fragilis , protein glycosylation is a fundamental and essential property as mutants with protein glycosylation defects have impaired growth and are unable to competitively colonize the mammalian intestine. In this study, we analysed the phenotype of B . fragilis mutants with defective protein glycosylation and found that the glycan added to proteins is comprised of a core glycan and an outer glycan. The genetic region encoding proteins for the synthesis of the outer glycan is conserved within a B acteroides species but divergent between species. Unlike the outer glycan, an antiserum raised to the core glycan reacted with all B acteroidetes species tested, from all four classes of the phylum. We found that diverse B acteroidetes species synthesize numerous glycoproteins and glycosylate proteins at the same three amino acid motif. The wide‐spread conservation of this protein glycosylation system within the phylum suggests that this system of post‐translational protein modification evolved early, before the divergence of the four classes of B acteroidetes, and has been maintained due to its physiological importance to the diverse species of this phylum.