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PDBsum entry 2di3
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Transcription
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PDB id
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2di3
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References listed in PDB file
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Key reference
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Title
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Structural and functional characterization of the lldr from corynebacterium glutamicum: a transcriptional repressor involved in l-Lactate and sugar utilization.
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Authors
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Y.G.Gao,
H.Suzuki,
H.Itou,
Y.Zhou,
Y.Tanaka,
M.Wachi,
N.Watanabe,
I.Tanaka,
M.Yao.
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Ref.
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Nucleic Acids Res, 2008,
36,
7110-7123.
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PubMed id
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Abstract
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LldR (CGL2915) from Corynebacterium glutamicum is a transcription factor
belonging to the GntR family, which is typically involved in the regulation of
oxidized substrates associated with amino acid metabolism. In the present study,
the crystal structure of LldR was determined at 2.05-A resolution. The structure
consists of N- and C-domains similar to those of FadR, but with distinct domain
orientations. LldR and FadR dimers achieve similar structures by domain
swapping, which was first observed in dimeric assembly of transcription factors.
A structural feature of Zn(2+) binding in the regulatory domain was also
observed, as a difference from the FadR subfamily. DNA microarray and DNase I
footprint analyses suggested that LldR acts as a repressor regulating
cgl2917-lldD and cgl1934-fruK-ptsF operons, which are indispensable for
l-lactate and fructose/sucrose utilization, respectively. Furthermore, the
stoichiometries and affinities of LldR and DNAs were determined by isothermal
titration calorimetry measurements. The transcriptional start site and
repression of LldR on the cgl2917-lldD operon were analysed by primer extension
assay. Mutation experiments showed that residues Lys4, Arg32, Arg42 and Gly63
are crucial for DNA binding. The location of the putative ligand binding cavity
and the regulatory mechanism of LldR on its affinity for DNA were proposed.
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