Affiliation:
1. IRIS, Chiron Vaccines
2. Unit of Electron Microscopy and Cryotechniques, Dipartmento Biologia Evolutiva, University of Siena, 53100 Siena, Italy
3. Children's Hospital Oakland Research Institute, Oakland, California 94609
Abstract
ABSTRACT
GNA33 is a membrane-bound lipoprotein with murein hydrolase activity that is present in all
Neisseria
species and well conserved in different meningococcal isolates. The protein shows 33% identity to a lytic transglycolase (MltA) from
Escherichia coli
and has been shown to be involved in the degradation of both insoluble murein sacculi and unsubstituted glycan strands. To study the function of the gene and its role in pathogenesis and virulence, a knockout mutant of a
Neisseria meningitidis
serogroup B strain was generated. The mutant exhibited retarded growth in vitro. Transmission electron microscopy revealed that the mutant grows in clusters which are connected by a continuous outer membrane, suggesting a failure in the separation of daughter cells. Moreover, sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of culture supernatant revealed that the mutant releases several proteins in the medium. The five most abundant proteins, identified by matrix-assisted laser desorption ionization-time-of-flight mass spectrometry analysis, belong to the outer membrane protein family. Finally, the mutant showed an attenuated phenotype, since it was not able to cause bacteremia in the infant rat model. We conclude that GNA33 is a highly conserved lipoprotein which plays an important role in peptidoglycan metabolism, cell separation, membrane architecture, and virulence.
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Immunology,Microbiology,Parasitology
Cited by
48 articles.
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