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Butterbur root extract and music therapy might be superior to placebo and may represent promising treatment approaches in the prophylaxis of paediatric migraine.

The 23 kDa two-domain periplasmic chaperone FimC from Escherichia coli is required for the assembly of type-1 pili, which are filamentous, highly oligomeric protein complexes anchored to the outer bacterial membrane that mediate adhesion of pathogenic E. coli strains to host cell surfaces. Here we identified the contact sites on the surface of the NMR structure of FimC that are responsible for the binding of the 28 kDa mannose-binding type-1 pilus subunit FimH by 15N and 1H NMR chemical shift mapping, using transverse relaxation-optimized spectroscopy (TROSY). The FimH-binding surface of FimC is formed nearly entirely by the N-terminal domain, and its extent and shape indicate that FimC binds a folded form of the pilus subunits.

Assembly of type 1 pili from Escherichia coli is mediated by FimC, a periplasmic chaperone (assembly factor) consisting of two immunoglobulin-like domains. FimC is assumed to recognize the individual pilus subunits in the periplasm mainly via their conserved C-terminal segments and to deliver the subunits to an assembly platform in the outer membrane. Here we present the first biochemical characterization of a periplasmic pilus chaperone and analyze the importance of the two chaperone domains for stability and function. Comparison of the isolated C-terminal domain with wild-type FimC revealed a strongly reduced thermodynamic stability, indicating strong interdomain interactions. The affinity of FimC toward a peptide corresponding to the 11 C-terminal residues of the type 1 pilus adhesin FimH is at least 1000-fold lower compared to binding of intact FimH, confirming that bacterial pilus chaperones, unlike other chaperones, specifically interact with folded pilus subunits.

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