This Article Full Text Full Text (PDF) All Versions of this Article: biophysj.104.044867v1 87/6/4271    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Jass, J. Articles by Axner, O. Search for Related Content PubMed PubMed Citation Articles by Jass, J. Articles by Axner, O.

Physical Properties of Escherichia coli P Pili Measured by Optical Tweezers

Jana Jass ^*, Staffan Schedin , Erik Fällman , Jörgen Ohlsson , Ulf J. Nilsson , Bernt Eric Uhlin ^¶ and Ove Axner 

^* Department of Microbiology and Immunology, The Lawson Health Research Institute, University of Western Ontario, London, Ontario, N6A 4V2, Canada; Department of Applied Physics and Electronics, and Department of Physics, Umeå University, SE-901 87 Umeå, Sweden; Organic and Bioorganic Chemistry, Lund University, SE-221 00 Lund, Sweden; and ^¶ Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden

Correspondence: Address reprint requests to Ove Axner, E-mail: ove.axner{at}physics.umu.se.

The mechanical behavior of individual P pili of uropathogenic Escherichia coli has been investigated using optical tweezers. P pili, whose main part constitutes the PapA rod, composed of 10³ PapA subunits in a helical arrangement, are distributed over the bacterial surface and mediate adhesion to host cells. They are particularly important in the pathogenesis of E. coli colonizing the upper urinary tract and kidneys. A biological model system has been established for in situ measurements of the forces that occur during mechanical stretching of pili. A mathematical model of the force-versus-elongation behavior of an individual pilus has been developed. Three elongation regions of pili were identified. In region I, P pili stretch elastically, up to a relative elongation of 16 ± 3%. The product of elasticity modulus and area of a P pilus, EA, was assessed to 154 ± 20 pN (n = 6). In region II, the quaternary structure of the PapA rod unfolds under a constant force of 27 ± 2 pN (n 100) by a sequential breaking of the interactions between adjacent layers of PapA subunits. This unfolding can elongate the pilus up to 7 ± 2 times. In region III, pili elongate in a nonlinear manner as a result of stretching until the bond ruptures.

This article has been cited by other articles:

				L. Jauffred, T. H. Callisen, and L. B. Oddershede Visco-Elastic Membrane Tethers Extracted from Escherichia coli by Optical Tweezers Biophys. J., December 1, 2007; 93(11): 4068 - 4075. [Abstract] [Full Text] [PDF]

				M. Andersson, B. E. Uhlin, and E. Fallman The Biomechanical Properties of E. coli Pili for Urinary Tract Attachment Reflect the Host Environment Biophys. J., November 1, 2007; 93(9): 3008 - 3014. [Abstract] [Full Text] [PDF]

				E. Miller, T. Garcia, S. Hultgren, and A. F. Oberhauser The Mechanical Properties of E. coli Type 1 Pili Measured by Atomic Force Microscopy Techniques Biophys. J., November 15, 2006; 91(10): 3848 - 3856. [Abstract] [Full Text] [PDF]

				M. Andersson, E. Fallman, B. E. Uhlin, and O. Axner Dynamic Force Spectroscopy of E. coli P Pili Biophys. J., October 1, 2006; 91(7): 2717 - 2725. [Abstract] [Full Text] [PDF]

				M. Andersson, E. Fallman, B. E. Uhlin, and O. Axner A Sticky Chain Model of the Elongation and Unfolding of Escherichia coli P Pili under Stress Biophys. J., March 1, 2006; 90(5): 1521 - 1534. [Abstract] [Full Text] [PDF]