Emmanuelle Darbon

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Spiramycin, a 16-membered macrolide antibiotic used in human medicine, is produced by Streptomyces ambofaciens; it comprises a polyketide lactone, platenolide, to which three deoxyhexose sugars are attached. In order to characterize the gene cluster governing the biosynthesis of spiramycin, several overlapping cosmids were isolated from an S. ambofaciens(More)
The main function of the bacterial phosphotransferase system is to transport and to phosphorylate mono- and disaccharides as well as sugar alcohols. However, the phosphotransferase system is also involved in regulation of carbon metabolism. In Grampositive bacteria, it is implicated in carbon catabolite repression and regulation of expression of catabolic(More)
The first structure of a glycerol kinase from a Gram-positive organism, Enterococcus casseliflavus, has been determined to 2.8 A resolution in the presence of glycerol and to 2.5 A resolution in the absence of substrate. The substrate-induced closure of 7 degrees is significantly smaller than that reported for hexokinase, a model for substrate-mediated(More)
Streptomyces ambofaciens synthesizes the macrolide antibiotic spiramycin. The biosynthetic gene cluster for spiramycin has been characterized for S. ambofaciens. In addition to the regulatory gene srmR (srm22), previously identified (M. Geistlich et al., Mol. Microbiol. 6:2019-2029, 1992), three putative regulatory genes had been identified by sequence(More)
The Bacillus subtilis glpFK operon encoding the glycerol transport facilitator (GlpF) and glycerol kinase (GlpK) is induced by glycerol-3-P and repressed by rapidly metabolizable sugars. Carbon catabolite repression (CCR) of glpFK is partly mediated via a catabolite response element cre preceding glpFK. This operator site is recognized by the catabolite(More)
Streptomyces lividans senses and adjusts to a situation of Pi limitation via the expression of genes of the pho regulon controlled by the two-component system PhoR/PhoP. Interestingly, an in silico analysis of the proteins encoded by the six genes located in divergence of phoR/phoP revealed that the latter bear features often found in metalloproteins(More)
The glpK genes of Enterococcus casseliflavus and Enterococcus faecalis, encoding glycerol kinase, the key enzyme of glycerol uptake and metabolism in bacteria, have been cloned and sequenced. The translated amino acid sequences exhibit strong homology to the amino acid sequences of other bacterial glycerol kinases. After expression of the enterococcal glpK(More)
Phosphorylation and dephosphorylation at Ser-46 in HPr, a phosphocarrier protein of the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) is controlled by the bifunctional HPr kinase/phosphorylase (HprK/P). In Gram-positive bacteria, P-Ser-HPr controls (1) sugar uptake via the PTS; (2) catabolite control protein A (CcpA)-mediated carbon(More)
Spiramycins are clinically important 16-member macrolide antibiotics produced by Streptomyces ambofaciens. Biosynthetic studies have established that the earliest lactonic intermediate in spiramycin biosynthesis, the macrolactone platenolide I, is synthesized by a type I modular polyketide synthase (PKS). Platenolide I then undergoes a series of post-PKS(More)
Crh of Bacillus subtilis exhibits 45% sequence identity when compared to histidine-containing protein (HPr), a phosphocarrier protein of the phosphoenolpyruvate (PEP):sugar phosphotransferase system (PTS). Crh can be phosphorylated by ATP at the regulatory Ser-46 and similar to P-Ser-HPr, P-Ser-Crh plays a role in carbon-catabolite repression. The sequence(More)