HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 280, Issue 36, 31489-31497, September 9, 2005

This Article Full Text Full Text (PDF) All Versions of this Article: 280/36/31489    most recent M506354200v1 Submit a Letter to Editor Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Moore, J. Articles by Derrick, J. P. Search for Related Content PubMed PubMed Citation Articles by Moore, J. Articles by Derrick, J. P. Social Bookmarking                      What's this?

Recognition of Saccharides by the OpcA, OpaD, and OpaB Outer Membrane Proteins from Neisseria meningitidis^*

Jeremy Moore, Simon E. S. Bailey, Zineb Benmechernene, Christos Tzitzilonis, Natalie J. E. Griffiths, Mumtaz Virji, and Jeremy P. Derrick¶

From the Faculty of Life Sciences, University of Manchester, Manchester, M60 1QD United Kingdom and the Department of Cellular and Molecular Medicine, University of Bristol, Bristol, BS8 1TD, United Kingdom

The adhesion of the pathogen Neisseria meningitidis to host cell surface proteoglycan, mediated by the integral outer membrane proteins OpcA and Opa, plays an important part in the processes of colonization and invasion by the bacterium. The precise specificities of the OpcA and Opa proteins are, however, unknown. Here we use a fluorescence-based binding assay to show that both proteins bind to mono- and disaccharides with high affinity. Binding of saccharides caused a quench in the intrinsic fluorescence emission of both proteins, and mutation of selected Tyr residues within the external loop regions caused a substantial decrease in fluorescence. We suggest that the intrinsic fluorescence arises from resonance energy transfer from Tyr to Trp residues in the -barrel portion of the structure. OpcA bound sialic acid with a K_d of 0.31 µM and was shown to be specific for pyranose saccharides. The binding specificities of two different Opa proteins were compared; unlike OpcA, neither protein bound to monosaccharides, but both bound to maltose, lactose, and sialic acid-containing oligosaccharides, with K_d values in the micromolar range. OpaB had a 10-fold higher affinity for sialic acid-containing ligands than OpaD as a result of the mutation Y165V, which was shown to restore this specificity to OpaD. Finally, the OpcA- and Opa-dependent adhesion of meningococci to epithelial cells was shown to be partially inhibited by exogenously added sialic acid and maltose. The results show that OpcA and the Opa proteins can be thought of as outer membrane lectins and that simple saccharides can modulate their recognition of complex proteoglycan receptors.

Received for publication, June 10, 2005 , and in revised form, July 7, 2005.

^* This work was funded with a research grant from the Wellcome Trust. The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

^¶ To whom correspondence should be addressed. Tel.: 44-161-3064207; Fax: 44-161-2360409; E-mail: Jeremy.Derrick{at}manchester.ac.uk.

CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				M. J. Callaghan, C. Buckee, N. D. McCarthy, A. B. Ibarz Pavon, K. A. Jolley, S. Faust, S. J. Gray, E. B. Kaczmarski, M. Levin, J. S. Kroll, et al. Opa Protein Repertoires of Disease-Causing and Carried Meningococci J. Clin. Microbiol., September 1, 2008; 46(9): 3033 - 3041. [Abstract] [Full Text] [PDF]

				L. A. Lewis, S. Ram, A. Prasad, S. Gulati, S. Getzlaff, A. M. Blom, U. Vogel, and P. A. Rice Defining Targets for Complement Components C4b and C3b on the Pathogenic Neisseriae Infect. Immun., January 1, 2008; 76(1): 339 - 350. [Abstract] [Full Text] [PDF]

				M. J. Callaghan, K. A. Jolley, and M. C. J. Maiden Opacity-Associated Adhesin Repertoire in Hyperinvasive Neisseria meningitidis Infect. Immun., September 1, 2006; 74(9): 5085 - 5094. [Abstract] [Full Text] [PDF]