Please use this identifier to cite or link to this item: http://hdl.handle.net/10362/4205
Title: Functional domains of Bacillus subtilis transcription factor AraR and identification of aminoacids important for nucleoprotein complex assembly and effector-binding.
Authors: Sá-Nogueira, Isabel de
Franco, Irina Saraiva
Mota, Luís Jaime
Soares, Cláudio Manuel
Issue Date: Mar-2006
Publisher: American Society for Microbiology
Citation: Franco, S. I., Mota, L. J., Soares, C. M., and I. Sá-Nogueira. (2006). Functional domains of Bacillus subtilis transcription factor AraR and identification of aminoacids important for nucleoprotein complex assembly and effector-binding. Journal of Bacteriology 188: 3024-3036.
Abstract: 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. We have used random mutagenesis, deletion, and construction of chimeric LexA-AraR fusion proteins to map the functional domains of AraR required for DNA binding, dimerization, and effector binding. Moreover, predictions for the functional role of specific residues were tested by site-directed mutagenesis. In vivo analysis identified particular amino acids required for dimer assembly, formation of the nucleoprotein complex, and composition of the sugar-binding cleft. This work presents a structural framework for the function of AraR and provides insight into the mechanistic mode of action of this modular repressor.
Description: Journal of Bacteriology (Apr 2006) 3024-3036
URI: http://hdl.handle.net/10362/4205
ISSN: 0021-9193 (Print)
1098-5530 (Online)
Appears in Collections:FCT: DCV - Artigos em revista internacional com arbitragem científica

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