title: Self-generated covalent cross-links in the cell-surface adhesins of Gram-positive bacteria.
abstract: The ability of bacteria to adhere to other cells or to surfaces depends on long, thin adhesive structures that are anchored to their cell walls. These structures include extended protein oligomers known as pili and single, multi-domain polypeptides, mostly based on multiple tandem Ig-like domains. Recent structural studies have revealed the widespread presence of covalent cross-links, not previously seen within proteins, which stabilize these domains. The cross-links discovered so far are either isopeptide bonds that link lysine side chains to the side chains of asparagine or aspartic acid residues or ester bonds between threonine and glutamine side chains. These bonds appear to be formed by spontaneous intramolecular reactions as the proteins fold and are strategically placed so as to impart considerable mechanical strength.
authors.affiliation: Maurice Wilkins Centre and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand en.baker@auckland.ac.nz.
authors.forename: Edward N
authors.initials: EN
authors.lastname: Baker
authors.affiliation: Maurice Wilkins Centre and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Squire
authors.affiliation: Maurice Wilkins Centre and School of Biological Sciences, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Paul G
authors.initials: PG
authors.lastname: Young
mesh_terms: D018829:Adhesins, Bacterial / Q000737:chemistry / Q000378:metabolism*; D001216:Asparagine / Q000737:chemistry; D001224:Aspartic Acid / Q000737:chemistry; D001422:Bacterial Adhesion; D036781:Fimbriae Proteins / Q000737:chemistry / Q000378:metabolism; D005973:Glutamine / Q000737:chemistry; D006094:Gram-Positive Bacteria / Q000502:physiology*; D008239:Lysine / Q000737:chemistry; D008958:Models, Molecular; D011487:Protein Conformation; D017510:Protein Folding; D054730:Protein Interaction Domains and Motifs; D055550:Protein Stability; D013912:Threonine / Q000737:chemistry
chemical_list: D018829:Adhesins, Bacterial; D005973:Glutamine; D036781:Fimbriae Proteins; D013912:Threonine; D001224:Aspartic Acid; D001216:Asparagine; D008239:Lysine
keywords: Ig-like domains; cell-surface adhesins; ester bond cross-links; isopeptide bond cross-links; mechanical strength; self-generated covalent bonds