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Catabolite Control Protein (catabolite + control_protein)
Selected AbstractsStructure of the transcription regulator CcpA from Lactococcus lactisACTA CRYSTALLOGRAPHICA SECTION D, Issue 4 2007Bernhard Loll Catabolite control protein A (CcpA) functions as master transcriptional regulator of carbon catabolism in Firmicutes. It belongs to the family of bacterial repressor/regulator proteins. Here, the crystal structure of the 76,kDa homodimeric CcpA protein from Lactococcus lactis subsp. lactis IL1403 is presented at 1.9,Å resolution in the absence of cognate DNA. The phases were derived by molecular replacement and the structure was refined to crystallographic R and Rfree factors of 0.177 and 0.211, respectively. The presence of a sulfate molecule in the direct vicinity of a putative effector-binding site in the monomer allowed the derivation of a model for the possible binding of small organic effector molecules. [source] RegM is required for optimal fructosyltransferase and glucosyltransferase gene expression in Streptococcus mutansFEMS MICROBIOLOGY LETTERS, Issue 1 2004Christopher M. Browngardt Abstract Glucosyltransferases (Gtfs) and fructosyltransferase (Ftf), and the exopolysaccharides they produce, facilitate bacterial adherence and biofilm formation, and enhance the virulence of Streptococcus mutans. In this study, we used continuous chemostat cultures and reporter gene fusions to study the expression of ftf and gtfBC in response to carbohydrate availability and pH, and to asses the role of a protein similar to catabolite control protein A (CcpA), RegM, in regulation of these genes. Expression of ftf was efficient at pH 7.0 and 6.0, but was repressed at pH 5.0 under glucose-excess conditions. At pH 7.0, ftf expression was 5-fold lower under glucose-limiting conditions than in cells growing with an excess of glucose. Expression of gtfBC was also sensitive, albeit to a lesser extent, to pH and glucose availability. Inactivation of regM resulted in decreases of as much as 10-fold in both ftf and gtfBC expression, depending on growth conditions. These findings reinforce the importance of pH and carbohydrate availability for expression of two primary virulence attributes of S. mutans and reveal a critical role for RegM in regulation of expression of both gtfBC and ftf. [source] Crystallization and preliminary X-ray analyses of catabolite control protein A, free and in complex with its DNA-binding siteACTA CRYSTALLOGRAPHICA SECTION D, Issue 1 2000Jan Tebbe The catabolite control protein (CcpA) from Bacillus megaterium is a member of the bacterial repressor protein family GalR/LacI. CcpA with an N-terminal His-tag was used for crystallization. Crystals of free CcpA and of CcpA in complex with the putative operator sequence (catabolite responsive elements, CRE) were obtained by vapour-diffusion techniques at 291,K using the hanging-drop method. CcpA crystals grown in the presence of polyethylene glycol 8000 belong to the hexagonal space group P6122 or P6522, with unit-cell parameters a = 74.4, c = 238.8,Å. These crystals diffract X-rays to 2.55,Å resolution and contain one monomer of the homodimeric protein per asymmetric unit. Crystals of the CcpA,CRE complex were obtained with ammonium sulfate as precipitant and belong to the tetragonal space group I4122, with unit-cell parameters a = 125, c = 400,Å and one complex per asymmetric unit. Although these co-crystals grew to a sufficient size, X-ray diffraction was limited to 8,Å resolution. [source] Structure of the apo form of the catabolite control protein A (CcpA) from Bacillus megaterium with a DNA-binding domainACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 4 2007Rajesh Kumar Singh Crystal structure determination of catabolite control protein A (CcpA) at 2.6,Å resolution reveals for the first time the structure of a full-length apo-form LacI-GalR family repressor protein. In the crystal structures of these transcription regulators, the three-helix bundle of the DNA-binding domain has only been observed in cognate DNA complexes; it has not been observed in other crystal structures owing to its mobility. In the crystal packing of apo-CcpA, the protein,protein contacts between the N-terminal three-helix bundle and the core domain consisted of interactions between the homodimers that were similar to those between the corepressor protein HPr and the CcpA N-subdomain in the ternary DNA complex. In contrast to the DNA complex, the apo-CcpA structure reveals large subdomain movements in the core, resulting in a complete loss of contacts between the N-subdomains of the homodimer. [source] | ||||||||||