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Two-dimensional structure of the Opc invasin from Neisseria meningitidis |
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| Authors: | Petra Merker Jan Tommassen Barica Kusecek Mumtaz Virji Dorothea Sesardic & Mark Achtman |
| Institution: | Max-Planck Institut fu¨r molekulare Genetik, Ihnestraße 73, D-14195 Berlin, Germany; Department of Molecular Cell Biology, Utrecht University, Padualaan 8, 3584 CH Utrecht, The Netherlands; Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK; Division of Bacteriology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar EN6 3QG, UK |
| Abstract: | A two-dimensional structural model was devised for the Opc outer membrane protein invasin which contains 10 transmembrane strands and five surface-exposed loops. One continuous epitope recognized by three monoclonal antibodies was localized to the tip of loop 2 by synthetic peptides and site-directed mutagenesis while a second, discontinuous epitope recognized by a fourth antibody was localized to loops 4 and 5 by insertion mutagenesis. These monoclonal antibodies are bactericidal and inhibit adhesion and invasion. Most of the T-cell epitopes defined by Wiertz et al. (1996) were localized to the transmembrane strands. Oligonucleotides encoding a foreign epitope (?) from Semliki Forest virus were inserted into Bgl II restriction sites created by site-directed mutagenesis. The ? epitopes inserted in all five predicted loops were recognized on the cell surface of live Escherichia coli bacteria by a monoclonal antibody and are exposed while ? epitopes in the N-terminus or three predicted turns were not. The results thus confirm important predictions of the model and define five permissive sites within surface-exposed loops which can be used to insert foreign epitopes. |
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