Journal article
The E. coli CsgB nucleator of curli assembles to β-sheet oligomers that alter the CsgA fibrillization mechanism
Proceedings of the National Academy of Sciences - PNAS, Vol.109(17), pp.6502-6507
04/24/2012
DOI: 10.1073/pnas.1204161109
PMCID: PMC3340089
PMID: 22493266
Abstract
Curli are extracellular proteinaceous functional amyloid aggregates produced by
Escherichia coli
,
Salmonella
spp., and other enteric bacteria. Curli mediate host cell adhesion and invasion and play a critical role in biofilm formation. Curli filaments consist of CsgA, the major subunit, and CsgB, the minor subunit. In vitro, purified CsgA and CsgB exhibit intrinsically disordered properties, and both are capable of forming amyloid fibers similar in morphology to those formed in vivo. However, in vivo, CsgA alone cannot form curli fibers, and CsgB is required for filament growth. Thus, we studied the aggregation of CsgA and CsgB both alone and together in vitro to investigate the different roles of CsgA and CsgB in curli formation. We found that though CsgA and CsgB individually are able to self-associate to form aggregates/fibrils, they do so using different mechanisms and with different kinetic behavior. CsgB rapidly forms structured oligomers, whereas CsgA aggregation is slower and appears to proceed through large amorphous aggregates before forming filaments. Substoichiometric concentrations of CsgB induce a change in the mechanism of CsgA aggregation from that of forming amorphous aggregates to that of structured intermediates similar to those of CsgB alone. Oligomeric CsgB accelerated the aggregation of CsgA, in contrast to monomeric CsgB, which had no effect. The structured β-strand oligomers formed by CsgB serve as nucleators for CsgA aggregation. These results provide insights into the formation of curli in vivo, especially the nucleator function of CsgB.
Details
- Title: Subtitle
- The E. coli CsgB nucleator of curli assembles to β-sheet oligomers that alter the CsgA fibrillization mechanism
- Creators
- Qin Shu - Department of Biochemistry and Molecular Biophysics, andScott L Crick - Department of Biochemistry and Molecular Biophysics, andJerome S Pinkner - Department of Molecular Microbiology and Center for Women’s Infectious Disease ResearchBradley Ford - Department of Molecular Microbiology and Center for Women’s Infectious Disease ResearchScott J Hultgren - Department of Molecular Microbiology and Center for Women’s Infectious Disease ResearchCarl Frieden - Department of Biochemistry and Molecular Biophysics, and
- Resource Type
- Journal article
- Publication Details
- Proceedings of the National Academy of Sciences - PNAS, Vol.109(17), pp.6502-6507
- DOI
- 10.1073/pnas.1204161109
- PMID
- 22493266
- PMCID
- PMC3340089
- NLM abbreviation
- Proc Natl Acad Sci U S A
- ISSN
- 0027-8424
- eISSN
- 1091-6490
- Publisher
- National Academy of Sciences
- Alternative title
- Differences in aggregation of CsgA and CsgB
- Language
- English
- Date published
- 04/24/2012
- Academic Unit
- Pathology
- Record Identifier
- 9984047746202771
Metrics
15 Record Views