Crystal structure of the PapC usher bound to the chaperone-adhesin PapD-PapGCrystal structure of the PapC usher bound to the chaperone-adhesin PapD-PapG

Structural highlights

6cd2 is a 3 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 3.7Å
Resources:FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT

Function

PAPD_ECOLX Binds and caps interactive surfaces on pilus subunits to prevent them from participating in non-productive interactions. Facilitates the import of subunits into the periplasm. May facilitate subunit folding. Chaperone-subunit complexes are then targeted to the PapC outer membrane usher where the chaperone must uncap from the subunits.

Publication Abstract from PubMed

Chaperone-usher pathway pili are extracellular proteinaceous fibres ubiquitously found on Gram-negative bacteria, and mediate host-pathogen interactions and biofilm formation critical in pathogenesis in numerous human diseases(1). During pilus assembly, an outer membrane macromolecular machine called the usher catalyses pilus biogenesis from the individual subunits that are delivered as chaperone-subunit complexes in the periplasm. The usher orchestrates pilus assembly using all five functional domains: a 24-stranded transmembrane beta-barrel translocation domain, a beta-sandwich plug domain, an amino-terminal periplasmic domain and two carboxy-terminal periplasmic domains (CTD1 and CTD2)(2-6). Despite extensive structural and functional characterization, the mechanism by which the usher is activated to initiate pilus biogenesis is unknown. Here, we present the crystal structure of the full-length PapC usher from Escherichia coli in complex with its cognate PapDG chaperone-subunit complex in a pre-activation state, elucidating molecular details of how the usher is specifically engaged by allosteric interactions with its substrate preceding activation and how the usher facilitates the transfer of subunits from the amino-terminal periplasmic domain to the CTDs during pilus assembly. This work elucidates the intricate workings of a molecular machine that catalyses chaperone-usher pathway pilus assembly and opens the door for the development of potent inhibitors to block pilus biogenesis.

Structural basis for usher activation and intramolecular subunit transfer in P pilus biogenesis in Escherichia coli.,Omattage NS, Deng Z, Pinkner JS, Dodson KW, Almqvist F, Yuan P, Hultgren SJ Nat Microbiol. 2018 Oct 1. pii: 10.1038/s41564-018-0255-y. doi:, 10.1038/s41564-018-0255-y. PMID:30275511[1]

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

See Also

References

  1. Omattage NS, Deng Z, Pinkner JS, Dodson KW, Almqvist F, Yuan P, Hultgren SJ. Structural basis for usher activation and intramolecular subunit transfer in P pilus biogenesis in Escherichia coli. Nat Microbiol. 2018 Oct 1. pii: 10.1038/s41564-018-0255-y. doi:, 10.1038/s41564-018-0255-y. PMID:30275511 doi:http://dx.doi.org/10.1038/s41564-018-0255-y

6cd2, resolution 3.70Å

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