1. Stabilizing Isopeptide Bonds Revealed in Gram-Positive Bacterial Pilus Structure
- Author
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Hae Joo Kang, Edward N. Baker, Fasséli Coulibaly, Thomas Proft, and Fiona Clow
- Subjects
Models, Molecular ,Chemical Phenomena ,Protein Conformation ,Streptococcus pyogenes ,Stereochemistry ,Protein subunit ,Amino Acid Motifs ,Molecular Sequence Data ,Crystallography, X-Ray ,medicine.disease_cause ,Pilus ,medicine ,Molecule ,Peptide bond ,Amino Acid Sequence ,chemistry.chemical_classification ,Isopeptide bond ,Multidisciplinary ,biology ,Chemistry, Physical ,Lysine ,Hydrogen Bonding ,Protein Structure, Tertiary ,Protein Subunits ,Pilus shaft ,chemistry ,Biochemistry ,Fimbriae, Bacterial ,Pilin ,biology.protein ,Fimbriae Proteins ,Asparagine ,Peptides - Abstract
Many bacterial pathogens have long, slender pili through which they adhere to host cells. The crystal structure of the major pilin subunit from the Gram-positive human pathogen Streptococcus pyogenes at 2.2 angstroms resolution reveals an extended structure comprising two all-β domains. The molecules associate in columns through the crystal, with each carboxyl terminus adjacent to a conserved lysine of the next molecule. This lysine forms the isopeptide bonds that link the subunits in native pili, validating the relevance of the crystal assembly. Each subunit contains two lysine-asparagine isopeptide bonds generated by an intramolecular reaction, and we find evidence for similar isopeptide bonds in other cell surface proteins of Gram-positive bacteria. The present structure explains the strength and stability of such Gram-positive pili and could facilitate vaccine development.
- Published
- 2007
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