Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Letter
  • Published:

Pilus chaperones represent a new type of protein-folding catalyst

Abstract

Adhesive type 1 pili from uropathogenic Escherichia coli strains have a crucial role during infection by mediating the attachment to and potentially the invasion of host tissue. These filamentous, highly oligomeric protein complexes are assembled by the ‘chaperone–usher’ pathway1, in which the individual pilus subunits fold in the bacterial periplasm and form stoichiometric complexes with a periplasmic chaperone molecule that is essential for pilus assembly2,3,4. The chaperone subsequently delivers the subunits to an assembly platform (usher) in the outer membrane, which mediates subunit assembly and translocation to the cell surface5,6,7,8. Here we show that the periplasmic type 1 pilus chaperone FimC binds non-native pilus subunits and accelerates folding of the subunit FimG by 100-fold. Moreover, we find that the FimC–FimG complex is formed quantitatively and very rapidly when folding of FimG is initiated in the presence of both FimC and the assembly-competent subunit FimF, even though the FimC–FimG complex is thermodynamically less stable than the FimF–FimG complex. FimC thus represents a previously unknown type of protein-folding catalyst, and simultaneously acts as a kinetic trap preventing spontaneous subunit assembly in the periplasm.

This is a preview of subscription content, access via your institution

Access options

Buy this article

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Schematic representation of type 1 pilus assembly according to the chaperone–usher pathway.
Figure 2: FimC forms transient complexes with folding pilus subunits and acts as a kinetic assembly trap.
Figure 3: FimC accelerates folding of FimGt by more than 100-fold.

Similar content being viewed by others

References

  1. Sauer, F. G. et al. Chaperone-assisted pilus assembly and bacterial attachment. Curr. Opin. Struct. Biol. 10, 548–556 (2000)

    Article  CAS  PubMed  Google Scholar 

  2. Lindberg, F., Tennent, J. M., Hultgren, S. J., Lund, B. & Normark, S. PapD, a periplasmic transport protein in P-pilus biogenesis. J. Bacteriol. 171, 6052–6058 (1989)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  3. Kuehn, M. J., Normark, S. & Hultgren, S. J. Immunoglobulin-like PapD chaperone caps and uncaps interactive surfaces of nascently translocated pilus subunits. Proc. Natl Acad. Sci. USA 88, 10586–10590 (1991)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  4. Jones, C. H. et al. FimC is a periplasmic PapD-like chaperone that directs assembly of type 1 pili in bacteria. Proc. Natl Acad. Sci. USA 90, 8397–8401 (1993)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  5. Klemm, P. & Christiansen, G. The fimD gene required for cell surface localization of Escherichia coli type 1 fimbriae. Mol. Gen. Genet. 220, 334–338 (1990)

    Article  CAS  PubMed  Google Scholar 

  6. Dodson, K. W., Jacob-Dubuisson, F., Striker, R. T. & Hultgren, S. J. Outer-membrane PapC molecular usher discriminately recognizes periplasmic chaperone-pilus subunit complexes. Proc. Natl Acad. Sci. USA 90, 3670–3674 (1993)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  7. Thanassi, D. G. et al. The PapC usher forms an oligomeric channel: implications for pilus biogenesis across the outer membrane. Proc. Natl Acad. Sci. USA 95, 3146–3151 (1998)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  8. Saulino, E. T., Bullitt, E. & Hultgren, S. J. Snapshots of usher-mediated protein secretion and ordered pilus assembly. Proc. Natl Acad. Sci. USA 97, 9240–9245 (2000)

    Article  ADS  CAS  PubMed  PubMed Central  Google Scholar 

  9. Hahn, E. et al. Exploring the 3D molecular architecture of Escherichia coli type 1 pili. J. Mol. Biol. 323, 845–857 (2002)

    Article  CAS  PubMed  Google Scholar 

  10. Choudhury, D. et al. X-ray structure of the FimC-FimH chaperone-adhesin complex from uropathogenic Escherichia coli. Science 285, 1061–1066 (1999)

    Article  CAS  PubMed  Google Scholar 

  11. Sauer, F. G. et al. Structural basis of chaperone function and pilus biogenesis. Science 285, 1058–1061 (1999)

    Article  CAS  PubMed  Google Scholar 

  12. Sauer, F. G., Pinkner, J. S., Waksman, G. & Hultgren, S. J. Chaperone priming of pilus subunits facilitates a topological transition that drives fiber formation. Cell 111, 543–551 (2002)

    Article  CAS  PubMed  Google Scholar 

  13. Zavialov, A. V. et al. Structure and biogenesis of the capsular F1 antigen from Yersinia pestis: preserved folding energy drives fiber formation. Cell 113, 587–596 (2003)

    Article  CAS  PubMed  Google Scholar 

  14. Zavialov, A. V. et al. Donor strand complementation mechanism in the biogenesis of non-pilus systems. Mol. Microbiol. 45, 983–995 (2002)

    Article  CAS  PubMed  Google Scholar 

  15. Jacob-Dubuisson, F., Striker, R. T. & Hultgren, S. J. Chaperone-assisted self-assembly of pili independent of cellular energy. J. Biol. Chem. 269, 12447–12455 (1994)

    CAS  PubMed  Google Scholar 

  16. Schmid, F. X. Mechanism of folding of ribonuclease A. Slow refolding is a sequential reaction via structural intermediates. Biochemistry 22, 4690–4696 (1983)

    Article  CAS  PubMed  Google Scholar 

  17. Balbach, J. & Schmid, F. X. in Protein Folding: Frontiers in Molecular Biology (ed. Pain, R.) (Oxford Univ. Press, Oxford, 2000)

    Google Scholar 

  18. Pugsley, A. P. The complete general secretory pathway in gram-negative bacteria. Microbiol. Rev. 57, 50–108 (1993)

    CAS  PubMed  PubMed Central  Google Scholar 

  19. Vetsch, M., Sebbel, P. & Glockshuber, R. Chaperone-independent folding of type 1 pilus domains. J. Mol. Biol. 322, 827–840 (2002)

    Article  CAS  PubMed  Google Scholar 

  20. Hartl, F. U. & Hayer-Hartl, M. Molecular chaperones in the cytosol: from nascent chain to folded protein. Science 295, 1852–1858 (2002)

    Article  ADS  CAS  PubMed  Google Scholar 

  21. Brinker, A. et al. Dual function of protein confinement in chaperonin-assisted protein folding. Cell 107, 223–233 (2001)

    Article  CAS  PubMed  Google Scholar 

  22. Jones, C. H., Danese, P. N., Pinkner, J. S., Silhavy, T. J. & Hultgren, S. J. The chaperone-assisted membrane release and folding pathway is sensed by two signal transduction systems. EMBO J. 16, 6394–6406 (1997)

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. Eder, J. & Fersht, A. R. Pro-sequence-assisted protein folding. Mol. Microbiol. 16, 609–614 (1995)

    Article  CAS  PubMed  Google Scholar 

  24. Baker, D., Sohl, J. L. & Agard, D. A. A protein-folding reaction under kinetic control. Nature 356, 263–265 (1992)

    Article  ADS  CAS  PubMed  Google Scholar 

  25. Frand, A. R., Cuozzo, J. W. & Kaiser, C. A. Pathways for protein disulphide bond formation. Trends Cell Biol. 10, 203–210 (2000)

    Article  CAS  PubMed  Google Scholar 

  26. Schiene-Fischer, C., Habazettl, J., Schmid, F. X. & Fischer, G. The hsp70 chaperone DnaK is a secondary amide peptide bond cis-trans isomerase. Nature Struct. Biol. 9, 419–424 (2002)

    Article  CAS  PubMed  Google Scholar 

  27. Hermanns, U., Sebbel, P., Eggli, V. & Glockshuber, R. Characterization of FimC, a periplasmic assembly factor for biogenesis of type 1 pili in Escherichia coli. Biochemistry 39, 11564–11570 (2000)

    Article  CAS  PubMed  Google Scholar 

  28. Nishiyama, M., Vetsch, M., Puorger, C., Jelesarov, I. & Glockshuber, R. Identification and characterization of the chaperone-subunit complex-binding domain from the type 1 pilus assembly platform FimD. J. Mol. Biol. 330, 513–525 (2003)

    Article  CAS  PubMed  Google Scholar 

Download references

Acknowledgements

We thank A. Bachmann and T. Kiefhaber for their assistance and discussions; A. Fritz for technical assistance; and R. Brunisholz for Edman sequencing and MALDI–TOF mass spectrometry. This work was supported by the Schweizerische Nationalfonds and the Swiss NCCR Program in Structural Biology.

Author information

Authors and Affiliations

Authors

Corresponding author

Correspondence to Rudi Glockshuber.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Supplementary information

Supplementary Table S1

The data in this table are derived from the fluorescence traces of FimGt folding kinetics (Supplementary Fig. S3) in the presence of the chaperone FimCYY, the subunit FimFF and the donor strand peptides DSFimC, DSFimF, and DSFimG. (PDF 98 kb)

Supplementary Figure S1

List of recombinant type1 pilus subunit constructs and synthetic donor strand peptides used in this study. (PDF 84 kb)

Supplementary Figure S2

Spectroscopic properties and thermodynamic stability of FimGt. The data illustrate that the tryptophan fluorescence of FimGt changes upon folding and that FimGt can fold also in the absence of any donor strand. (PDF 91 kb)

Supplementary Figure S3

Stopped flow fluorescence traces of FimGt refolding. Folding of FimGt is slow and neither the partner subunit FimFF nor synthetic donor strand peptides influence FimGt folding significantly. In contrast, the reaction catalysed by the chaperone FimC exhibits very rapid and complex folding kinetics. (PDF 294 kb)

Supplementary Figure S4

The figure shows interrupted refolding experiments that follow the formation of native complexes between FimGt and various donor strand peptides. In addition, the determination of the apparent affinity of FimGt for the corresponding donor strand peptides is shown. (PDF 95 kb)

Supplementary Figure S5

Comparison of FimC and the tryptophan-free variant FimCYY with respect to stability, spectroscopic properties and function. The results indicate that FimCYY retains the ability of FimC to form soluble complexes with subunits in vivo despite its lowered intrinsic stability. (PDF 254 kb)

Supplementary Figure S6

Interrupted refolding was used to monitor the formation of native FimGt in the presence of both FimCYY and cyclophilin. Periplasmic cyclophilin does not abolish the slow phase in chaperone-assisted formation of native FimGt. (PDF 79 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Vetsch, M., Puorger, C., Spirig, T. et al. Pilus chaperones represent a new type of protein-folding catalyst. Nature 431, 329–333 (2004). https://doi.org/10.1038/nature02891

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature02891

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing