Stabilizing isopeptide bonds revealed in gram-positive bacterial pilus structure

Hae Joo Kang, Fasseli Joseph Coulibaly, Fiona Clow, Thomas Proft, Edward N Baker

Research output: Contribution to journalArticleResearchpeer-review

280 Citations (Scopus)


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-beta 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.
Original languageEnglish
Pages (from-to)1625 - 1628
Number of pages4
Issue number5856
Publication statusPublished - 2007
Externally publishedYes

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