1L4I

Crystal Structure of the Periplasmic Chaperone SfaE

Summary for 1L4I

• Entry DOI: 10.2210/pdb1l4i/pdb
• Descriptor: SfaE PROTEIN (2 entities in total)
• Functional Keywords: periplasmic chaperone, immunoglobulin fold, chaperone
• Biological source: Escherichia coli
• Cellular location: Periplasm (By similarity): P62609
• Total number of polymer chains: 2
• Total formula weight: 45491.83

Authors

Knight, S.D.,Choudhury, D.,Hultgren, S.,Pinkner, J.,Stojanoff, V.,Thompson, A. (deposition date: 2002-03-05, release date: 2002-06-12, Last modification date: 2024-02-14)

Primary citation

Knight, S.D.,Choudhury, D.,Hultgren, S.,Pinkner, J.,Stojanoff, V.,Thompson, A.
Structure of the S pilus periplasmic chaperone SfaE at 2.2 A resolution.
Acta Crystallogr.,Sect.D, 58:1016-1022, 2002

PubMed Abstract: S pili are sialic acid binding hair-like appendages expressed by pathogenic strains of Escherichia coli. The presence of S pili has been implicated as a virulence factor in both urinary-tract infections and new-born meningitis. Assembly of S pili proceeds via the ubiquitous chaperone/usher pathway. Previously, structures of the homologous chaperones PapD and FimC involved in assembly of P and type-1 pili, respectively, have been solved. Here, the 2.2 A X-ray structure of the S pilus chaperone SfaE is reported. SfaE has the same overall L-shaped structure as PapD and FimC, with two immunoglobulin-like domains oriented at about a 90 degrees angle to each other. Conserved residues in the subunit-binding cleft known to be critical for chaperone function occupy essentially identical positions in SfaE, FimC and PapD. As in free PapD and FimC, the long F1-G1 loop connecting the two last strands of the N-terminal domain is disordered. SfaE crystallizes as a dimer with an extensive dimer interface involving the subunit-binding surfaces of the chaperone. Dimerization via these regions has previously been observed for PapD and might be a general side effect arising from the subunit-binding properties of periplasmic chaperones. The domain interface contains an extended hydrogen-bond network involving three invariant charged residues and two structurally conserved water molecules. It is suggested that disruption of the domain interactions may destabilize the N-terminal domain through exposure of three conserved hydrophobic residues, thereby promoting release of pilus subunits during pilus assembly.

PubMed: 12037304
DOI: 10.1107/S0907444902005954

Experimental method

X-RAY DIFFRACTION (2.2 Å)