Multitask ATPases (NBDs) of bacterial ABC importers type I and their interspecies exchangeability.

ATP-binding cassette (ABC) type I importers are widespread in bacteria and play a crucial role in its survival and pathogenesis. They share the same modular architecture comprising two intracellular nucleotide-binding domains (NBDs), two transmembrane domains (TMDs) and a substrate-binding protein. The NBDs bind and hydrolyze ATP, thereby generating conformational changes that are coupled to the TMDs and lead to substrate translocation.

The MsmX ATPase plays a crucial role in pectin mobilization by Bacillus subtilis.

Carbohydrates from plant cell walls are often found as heteropolysaccharides intertwined with each other. For competitive advantage against other microorganisms, and ability to fully exploit available carbon and energy sources, Bacillus subtilis possesses a high number of proteins dedicated to the uptake of mono- and oligosaccharides. Here, we characterize transporter complexes, belonging to the ATP-binding cassette (ABC) superfamily, involved in the uptake of oligosaccharides commonly found in pectin.

Towards novel amino acid-base contacts in gene regulatory proteins: AraR--a case study.

AraR is a transcription factor involved in the regulation of carbon catabolism in Bacillus subtilis. This regulator belongs to the vast GntR family of helix-turn-helix (HTH) bacterial metabolite-responsive transcription factors. In this study, AraR-DNA specific interactions were analysed by an in vitro missing-contact probing and validated using an in vivo model.

The importance of the Abn2 calcium cluster in the endo-1,5-arabinanase activity from Bacillus subtilis.

Arabinanase is a glycosyl hydrolase that is able to cleave the glycosidic bonds of α-1,5-L-arabinan, releasing arabino-oligosaccharides and L-arabinose. The enzyme has two domains, an N-terminal catalytic domain with a characteristic β-propeller fold and a C-terminal domain whose function is unknown. A calcium ion, located near the catalytic site, serves to stabilize the N-terminal domain, but it has also been proposed to play a key role in the enzyme mechanism.

Characterization and regulation of a bacterial sugar phosphatase of the haloalkanoate dehalogenase superfamily, AraL, from Bacillus subtilis.

AraL from Bacillus subtilis is a member of the ubiquitous haloalkanoate dehalogenase superfamily. The araL gene has been cloned, over-expressed in Escherichia coli and its product purified to homogeneity. The enzyme displays phosphatase activity, which is optimal at neutral pH (7.

New evidence for the role of calcium in the glycosidase reaction of GH43 arabinanases.

Endo-1,5-α-L-arabinanases are glycosyl hydrolases that are able to cleave the glycosidic bonds of α-1,5-L-arabinan, releasing arabino-oligosaccharides and L-arabinose. Two extracellular endo-1,5-α-L-arabinanases have been isolated from Bacillus subtilis, BsArb43A and BsArb43B (formally named AbnA and Abn2, respectively). BsArb43B shows low sequence identity with previously characterized 1,5-α-L-arabinanases and is a much larger enzyme.

A multitask ATPase serving different ABC-type sugar importers in Bacillus subtilis.

Bacillus subtilis is able to utilize arabinopolysaccharides derived from plant biomass. Here, by combining genetic and physiological analyses we characterize the AraNPQ importer and identify primary and secondary transporters of B. subtilis involved in the uptake of arabinosaccharides.

Two distinct arabinofuranosidases contribute to arabino-oligosaccharide degradation in Bacillus subtilis.

Bacillus subtilis produces alpha-l-arabinofuranosidases (EC 3.2.1.

Overproduction, crystallization and preliminary X-ray characterization of Abn2, an endo-1,5-alpha-arabinanase from Bacillus subtilis.

Two Bacillus subtilis extracellular endo-1,5-alpha-L-arabinanases, AbnA and Abn2, belonging to glycoside hydrolase family 43 have been identified. The recently characterized Abn2 protein hydrolyzes arabinan and has low identity to other reported 1,5-alpha-L-arabinanases. Abn2 and its selenomethionine (SeMet) derivative have been purified and crystallized.

Characterization of abn2 (yxiA), encoding a Bacillus subtilis GH43 arabinanase, Abn2, and its role in arabino-polysaccharide degradation.

The extracellular depolymerization of arabinopolysaccharides by microorganisms is accomplished by arabinanases, xylanases, and galactanases. Here, we characterize a novel endo-alpha-1,5-l-arabinanase (EC 3.2.

trans-Acting factors and cis elements involved in glucose repression of arabinan degradation in Bacillus subtilis.

In Bacillus subtilis, the synthesis of enzymes involved in the degradation of arabinose-containing polysaccharides is subject to carbon catabolite repression (CCR). Here we show that CcpA is the major regulator of repression of the arabinases genes in the presence of glucose. CcpA acts via binding to one cre each in the promoter regions of the abnA and xsa genes and to two cres in the araABDLMNPQ-abfA operon.

Probing key DNA contacts in AraR-mediated transcriptional repression of the Bacillus subtilis arabinose regulon.

In the absence of arabinose, the AraR transcription factor represses the expression of genes involved in the utilization of arabinose, xylose and galactose in Bacillus subtilis. AraR exhibits a chimeric organization: the N-terminal DNA-binding region belongs to the GntR family and the C-terminal effector-binding domain is homologous to the GalR/LacI family. Here, the AraR-DNA-binding interactions were characterized in vivo and in vitro.

Functional domains of the Bacillus subtilis transcription factor AraR and identification of amino acids important for nucleoprotein complex assembly and effector binding.

The Bacillus subtilis AraR transcription factor represses at least 13 genes required for the extracellular degradation of arabinose-containing polysaccharides, transport of arabinose, arabinose oligomers, xylose, and galactose, intracellular degradation of arabinose oligomers, and further catabolism of this sugar. AraR exhibits a chimeric organization comprising a small N-terminal DNA-binding domain that contains a winged helix-turn-helix motif similar to that seen with the GntR family and a larger C-terminal domain homologous to that of the LacI/GalR family. Here, a model for AraR was derived based on the known crystal structures of the FadR and PurR regulators from Escherichia coli.

Purification, characterization and functional analysis of an endo-arabinanase (AbnA) from Bacillus subtilis.

Bacillus subtilis synthesizes at least one arabinanase encoded by the abnA gene that is able to degrade the polysaccharide arabinan. Here, we report the expression in Escherichia coli of the full-length abnA coding region with a His6-tag fused to the C-terminus. The recombinant protein was secreted to the periplasmic space and correctly processed by the E.

Transcriptional regulation of genes encoding arabinan-degrading enzymes in Bacillus subtilis.

Bacillus subtilis produces hemicellulases capable of releasing arabinosyl oligomers and arabinose from plant cell walls. In this work, we characterize the transcriptional regulation of three genes encoding arabinan-degrading enzymes that are clustered with genes encoding enzymes that further catabolize arabinose. The abfA gene comprised in the metabolic operon araABDLMNPQ-abfA and the xsa gene located 23 kb downstream most probably encode alpha-L-arabinofuranosidases (EC 3.

Distinct molecular mechanisms involved in carbon catabolite repression of the arabinose regulon in Bacillus subtilis.

The Bacillus subtilis proteins involved in the utilization of L-arabinose are encoded by the araABDLMNPQ-abfA metabolic operon and by the araE/araR divergent unit. Transcription from the ara operon, araE transport gene and araR regulatory gene is induced by L-arabinose and negatively controlled by AraR. Additionally, expression of both the ara operon and the araE gene is regulated at the transcriptional level by glucose repression.