2m5g

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Solution structure of FimA wtSolution structure of FimA wt

Structural highlights

2m5g is a 1 chain structure with sequence from Escherichia coli K-12. Full experimental information is available from OCA. For a guided tour on the structure components use FirstGlance.
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

FIMA1_ECOLI Fimbriae (also called pili), polar filaments radiating from the surface of the bacterium to a length of 0.5-1.5 micrometers and numbering 100-300 per cell, enable bacteria to colonize the epithelium of specific host organs.

Publication Abstract from PubMed

Type 1 pili are filamentous organelles mediating the attachment of uropathogenic Escherichia coli to epithelial cells of host organisms. The helical pilus rod consists of up to 3000 copies of the main structural subunit FimA that interact via donor strand complementation, where the incomplete Ig-like fold of FimA is completed by insertion of the N-terminal extension (donor strand) of the following FimA subunit. Recently, it was shown that FimA also exists in a monomeric, assembly-incompetent form and that FimA monomers act as inhibitors of apoptosis in infected host cells. Here we present the NMR structure of monomeric wild-type FimA with its natural N-terminal donor strand complementing the Ig fold. Compared to FimA subunits in the assembled pilus, intramolecular self-complementation in the monomer stabilizes the FimA fold with significantly less interactions, and the natural FimA donor strand is inserted in the opposite orientation. In addition, we show that a motif of two glycine residues in the FimA donor strand, separated by five residues, is the prerequisite of the alternative, parallel donor strand insertion mechanism in the FimA monomer and that this motif is preserved in FimA homologs of many enteroinvasive pathogens. We conclude that FimA is a unique case of a protein with alternative, functionally relevant folding possibilities, with the FimA polymer forming the highly stable pilus rod and the FimA monomer promoting pathogen propagation by apoptosis suppression of infected epithelial target cells.

Intramolecular Donor Strand Complementation in the E. coli Type 1 Pilus Subunit FimA Explains the Existence of FimA Monomers As Off-Pathway Products of Pilus Assembly That Inhibit Host Cell Apoptosis.,Walczak MJ, Puorger C, Glockshuber R, Wider G J Mol Biol. 2013 Oct 30. pii: S0022-2836(13)00686-4. doi:, 10.1016/j.jmb.2013.10.029. PMID:24184277[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

See Also

References

  1. Walczak MJ, Puorger C, Glockshuber R, Wider G. Intramolecular Donor Strand Complementation in the E. coli Type 1 Pilus Subunit FimA Explains the Existence of FimA Monomers As Off-Pathway Products of Pilus Assembly That Inhibit Host Cell Apoptosis. J Mol Biol. 2013 Oct 30. pii: S0022-2836(13)00686-4. doi:, 10.1016/j.jmb.2013.10.029. PMID:24184277 doi:http://dx.doi.org/10.1016/j.jmb.2013.10.029
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