Abstract
The purine repressor (PurR) consists of two functional domains: an N-terminal DNA-binding domain and a C-terminal corepressor-binding domain. Recently, the structure of PurR-corepressor-operator ternary complex was determined by X-ray crystallography. In the complex the DNA-binding domain, consisting of 56 amino acids, was composed of four helices. Here, we have determined the solution structure of the DNA-binding domain in its DNA free state by NMR. It consists of three helices and the fourth helix (the hinge helix) region is diordered. The architecture of the first three helices of its DNA free state is very similar to that of its DNA-bound form. The hinge helix is induced by the specific DNA binding and by the dimerization of PurR which is provided by the corepressor-binding domain.
MeSH terms
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Bacterial Proteins / chemistry*
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Bacterial Proteins / genetics
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Bacterial Proteins / metabolism*
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Binding Sites
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DNA, Bacterial / metabolism*
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DNA-Binding Proteins / chemistry*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Dimerization
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Escherichia coli / genetics
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Escherichia coli / metabolism
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Escherichia coli Proteins*
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Magnetic Resonance Spectroscopy
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Models, Molecular
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Molecular Structure
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Protein Conformation
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
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Repressor Proteins / chemistry*
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Repressor Proteins / genetics
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Repressor Proteins / metabolism*
Substances
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Bacterial Proteins
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DNA, Bacterial
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DNA-Binding Proteins
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Escherichia coli Proteins
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PurR protein, Bacteria
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PurR protein, E coli
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Recombinant Proteins
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Repressor Proteins