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Tracheal cytotoxin (TCT) was originally described as the minimal effector that was able to reproduce the cytotoxic response of Bordetella pertussis on ciliated epithelial cells. This molecule triggers pleiotropic effects such as immune stimulation or slow-wave sleep modulation. Further characterization identified TCT as a specific diaminopimelic acid(More)
The Drosophila peptidoglycan recognition protein SA (PGRP-SA) is critically involved in sensing bacterial infection and activating the Toll signaling pathway, which induces the expression of specific antimicrobial peptide genes. We have determined the crystal structure of PGRP-SA to 2.2-A resolution and analyzed its peptidoglycan (PG) recognition and(More)
The Drosophila immune system discriminates between different classes of infectious microbes and responds with pathogen-specific defense reactions through selective activation of the Toll and the immune deficiency (Imd) signaling pathways. The Toll pathway mediates most defenses against Gram-positive bacteria and fungi, whereas the Imd pathway is required to(More)
N-acetylglucosamine 1-phosphate uridyltransferase (GlmU) is a cytoplasmic bifunctional enzyme involved in the biosynthesis of the nucleotide-activated UDP-GlcNAc, which is an essential precursor for the biosynthetic pathways of peptidoglycan and other components in bacteria. The crystal structure of a truncated form of GlmU has been solved at 2.25 A(More)
Chlamydiaceae are obligate intracellular bacteria that do not synthesise detectable peptidoglycan although they possess an almost complete arsenal of genes encoding peptidoglycan biosynthetic activities. In this paper, the murF gene from Chlamydia trachomatis was shown to be capable of complementing a conditional Escherichia coli mutant impaired in(More)
The glucosamine-1-phosphate acetyltransferase activity but not the uridyltransferase activity of the bifunctional GlmU enzyme from Escherichia coli was lost when GlmU was stored in the absence of beta-mercaptoethanol or incubated with thiol-specific reagents. The enzyme was protected from inactivation in the presence of its substrate acetyl coenzyme A(More)
The Drosophila host defense against gram-negative bacteria is mediated by the Imd pathway upon sensing of peptidoglycan by the peptidoglycan recognition protein (PGRP)-LC. Here we report a functional analysis of PGRP-LB, a catalytic member of the PGRP family. We show that PGRP-LB is a secreted protein regulated by the Imd pathway. Biochemical studies(More)
Tracheal cytotoxin (TCT), a naturally occurring fragment of Gram-negative peptidoglycan, is a potent elicitor of innate immune responses in Drosophila. It induces the heterodimerization of its recognition receptors, the peptidoglycan recognition proteins (PGRPs) LCa and LCx, which activates the immune deficiency pathway. The crystal structure at 2.1(More)
In Escherichia coli many enzymes including MurG are directly involved in the synthesis and assembly of peptidoglycan. MurG is an essential glycosyltransferase catalysing the last intracellular step of peptidoglycan synthesis. To elucidate its role during elongation and division events, localization of MurG using immunofluorescence microscopy was performed.(More)
Innate immune recognition of microbes is a complex process that can be influenced by both the host and the microbe. Drosophila uses two distinct immune signaling pathways, the Toll and immune deficiency (Imd) pathways, to respond to different classes of microbes. The Toll pathway is predominantly activated by Gram-positive bacteria and fungi, while the Imd(More)