3QDH

Crystal structure of Actinomyces fimbrial adhesin FimA

Summary for 3QDH

• Entry DOI: 10.2210/pdb3qdh/pdb
• Descriptor: Fimbrial structural subunit, ZINC ION (3 entities in total)
• Functional Keywords: isopeptide bonds, actinomyces type 2 fimbriae, cnaa/dev-igg fold, cnab/igg-rev fold, gram-positive bacterial cell wall protein, fimbrial structural subunit, cell ahdesion, pilin, cell adhesion
• Biological source: Actinomyces naeslundii
• Total number of polymer chains: 1
• Total formula weight: 31082.86

Authors

Devarajan, B.,Krishnan, V.,Narayana, S.V.L. (deposition date: 2011-01-18, release date: 2011-08-24, Last modification date: 2024-10-09)

Primary citation

Mishra, A.,Devarajan, B.,Reardon, M.E.,Dwivedi, P.,Krishnan, V.,Cisar, J.O.,Das, A.,Narayana, S.V.,Ton-That, H.
Two autonomous structural modules in the fimbrial shaft adhesin FimA mediate Actinomyces interactions with streptococci and host cells during oral biofilm development.
Mol.Microbiol., 81:1205-1220, 2011

PubMed Abstract: By combining X-ray crystallography and modelling, we describe here the atomic structure of distinct adhesive moieties of FimA, the shaft fimbrillin of Actinomyces type 2 fimbriae, which uniquely mediates the receptor-dependent intercellular interactions between Actinomyces and oral streptococci as well as host cells during the development of oral biofilms. The FimA adhesin is built with three IgG-like domains, each of which harbours an intramolecular isopeptide bond, previously described in several Gram-positive pilins. Genetic and biochemical studies demonstrate that although these isopeptide bonds are dispensable for fimbrial assembly, cell-cell interactions and biofilm formation, they contribute significantly to the proteolytic stability of FimA. Remarkably, FimA harbours two autonomous adhesive modules, which structurally resemble the Staphylococcus aureus Cna B domain. Each isolated module can bind the plasma glycoprotein asialofetuin as well as the polysaccharide receptors present on the surface of oral streptococci and epithelial cells. Thus, FimA should serve as an excellent paradigm for the development of therapeutic strategies and elucidating the precise molecular mechanisms underlying the interactions between cellular receptors and Gram-positive fimbriae.

PubMed: 21696465
DOI: 10.1111/j.1365-2958.2011.07745.x

Experimental method

X-RAY DIFFRACTION (1.9 Å)