6r74

N-terminally reversed variant of FimA E. coli

spinqualitylabelsall models 6r74, resolution 1.81Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6r74 is a 1 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.81Å Ligands: SO4 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 FimA is the main structural subunit of adhesive type 1 pili from uropathogenic Escherichia coli strains. Up to 3000 copies of FimA assemble to the helical pilus rod through a mechanism termed donor strand complementation, in which the incomplete immunoglobulin-like fold of each FimA subunit is complemented by the N-terminal extension (Nte) of the next subunit. The Nte of FimA, which exhibits a pseudo-palindromic sequence, is inserted in an antiparallel orientation relative to the last beta-strand of the preceding subunit in the pilus. The resulting subunit-subunit interactions are extraordinarily stable against dissociation and unfolding. Alternatively, FimA can fold to a self-complemented monomer with anti-apoptotic activity, in which the Nte inserts intramolecularly into the FimA core in the opposite, parallel orientation. The FimA monomers, however, show dramatically lower thermodynamic stability compared to FimA subunits in the assembled pilus. Using self-complemented FimA variants with reversed, pseudo-palindromic extensions, we demonstrate that the high stability of FimA polymers is primarily caused by the specific interactions between the side chains of the Nte residues and the FimA core, and not by the antiparallel orientation of the donor strand alone. In addition, we demonstrate that non-equilibrium two-state folding, a hallmark of FimA with the Nte inserted in the pilus rod-like, antiparallel orientation, only depends on the identity of the inserted Nte side chains, and not on Nte orientation. Donor strand sequence, rather than donor strand orientation, determines the stability and non-equilibrium folding of the type 1 pilus subunit FimA.,Zyla DS, Echeverria B, Glockshuber R J Biol Chem. 2020 Jul 10. pii: RA120.014324. doi: 10.1074/jbc.RA120.014324. PMID:32651228 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Pilin 3D structures

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