| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
1 Centre for Molecular Biology and Neuroscience and Institute of Microbiology, University of Oslo, Norway
2 Centre for Molecular Biology and Neuroscience and Institute of Microbiology, Rikshospitalet-Radiumhospitalet Medical Centre, Norway
3 Faculty of Life Sciences, The University of Manchester, Sackville Street, PO Box 88, Manchester M60 1QD, UK
4 Division of Medical Microbiology, Department of Molecular and Clinical Medicine, Faculty of Health Sciences, Linköping University, Sweden
Correspondence
Tone Tønjum
tone.tonjum{at}medisin.uio.no
Neisseria meningitidis is the causative agent of epidemic meningococcal meningitis and septicaemia. Type IV pili are surface organelles that mediate a variety of functions, including adhesion, twitching motility, and competence for DNA binding and uptake in transformation. The secretin PilQ is required for type IV pilus expression at the cell surface, and forms a dodecameric cage-like macromolecular complex in the meningococcal outer membrane. PilQ-null mutants are devoid of surface pili, and prevailing evidence suggests that the PilQ complex facilitates extrusion and retraction of type IV pili across the outer membrane. Defining the orientation of the meningococcal PilQ complex in the membrane is a prerequisite for understanding the structure–function relationships of this important protein in pilus biology. In order to begin to define the topology of the PilQ complex in the outer membrane, polyhistidine insertions in N- and C-terminal regions of PilQ were constructed, and their subcellular locations examined. Notably, the insertion epitopes at residues 205 and 678 were located within the periplasm, whereas residue 656 was exposed at the outer surface of the outer membrane. Using electron microscopy with Ni-NTA gold labelling, it was demonstrated that the insertion at residue 205 within the N-terminus mapped to a site on the arm-like features of the 3D structure of the PilQ multimer. Interestingly, mutation of the same region gave rise to an increase in vancomycin permeability through the PilQ complex. The results yield novel information on the PilQ N-terminal location and function in the periplasm, and reveal a complex organization of the membrane-spanning secretin in vivo.
A supplementary table and supplementary figures are available with the online version of this paper.
This article has been cited by other articles:
|
|
 |
|
  S. Sinha, O. H. Ambur, P. R. Langford, T. Tonjum, and J. S. Kroll Reduced DNA binding and uptake in the absence of DsbA1 and DsbA2 of Neisseria meningitidis due to inefficient folding of the outer-membrane secretin PilQ Microbiology, January 1, 2008; 154(1): 217 - 225. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. V. Balasingham, R. F. Collins, R. Assalkhou, H. Homberset, S. A. Frye, J. P. Derrick, and T. Tonjum Interactions between the Lipoprotein PilP and the Secretin PilQ in Neisseria meningitidis J. Bacteriol., August 1, 2007; 189(15): 5716 - 5727. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. Assalkhou, S. Balasingham, R. F. Collins, S. A. Frye, T. Davidsen, A. V. Benam, M. Bjoras, J. P. Derrick, and T. Tonjum The outer membrane secretin PilQ from Neisseria meningitidis binds DNA Microbiology, May 1, 2007; 153(5): 1593 - 1603. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
