Biomechanical and Structural features of CS2 fimbriae of Enterotoxigenic Escherichia coli
2015 (English)In: Biophysical Journal, ISSN 0006-3495, E-ISSN 1542-0086, Vol. 109, no 1, 49-56 p.Article in journal (Refereed) Published
Enterotoxigenic Escherichia coli (ETEC) are a major cause of diarrhea worldwide, and infection of children in underdeveloped countries often leads to high mortality rates. Isolated ETEC express a plethora of colonization factors (fimbriae/pili), of which CFA/I and CFA/II that are assembled via the alternate chaperone pathway (ACP), are amongst the most common. Fimbriae are filamentous structures, whose shafts are primarily composed of helically arranged single pilin-protein subunits, with a unique biomechanical capability allowing them to unwind and rewind. A sustained ETEC infection, under adverse conditions of dynamic shear forces, is primarily attributed to this biomechanical feature of ETEC fimbriae. Recent understandings about the role of fimbriae as virulence factors are pointing to an evolutionary adaptation of their structural and biomechanical features. In this work, we investigated the biophysical properties of CS2 fimbriae from the CFA/II group. Homology modelling its major structural subunit CotA reveals structural clues and these are related to the niche in which they are expressed. Using optical tweezers force spectroscopy we found that CS2 fimbriae unwind at a constant force of 10 pN and have a corner velocity of 1300 nm/s, i.e., the velocity at which the force required for unwinding rises exponentially with increased speed. The biophysical properties of CS2 fimbriae assessed in this work classify them into a low-force unwinding group of fimbriae together with the CFA/I and CS20 fimbriae expressed by ETEC strains. The three fimbriae are expressed by ETEC, colonize in similar gut environments, and exhibit similar biophysical features, but differ in their biogenesis. Our observation suggests that the environment has a strong impact on the biophysical characteristics of fimbriae expressed by ETEC.
Place, publisher, year, edition, pages
Elsevier, 2015. Vol. 109, no 1, 49-56 p.
pili, optical tweezers, bacteria, pathogenesis, virulence factors
Other Physics Topics
Research subject Physics
IdentifiersURN: urn:nbn:se:umu:diva-103247DOI: 10.1016/j.bpj.2015.05.022OAI: oai:DiVA.org:umu-103247DiVA: diva2:812483
FunderSwedish Research Council, 621-2013-5379
This work was supported by NIH (GM05722 and RR025434 to E.B.), the Swedish Research Council (621-2013-5379 to M.A. and the Carl Trygger foundation to M.A.2015-05-192015-05-192016-04-29Bibliographically approved