Abstract
The crystal structure of a DNA-binding domain of PHO4 complexed with DNA at 2.8 A resolution revealed that the domain folds into a basic-helix-loop-helix (bHLH) motif with a long but compact loop that contains a short alpha-helical segment. This helical structure positions a tryptophan residue into an aromatic cluster so as to make the loop compact. PHO4 binds to DNA as a homodimer with direct reading of both the core E-box sequence CACGTG and its 3'-flanking bases. The 3'-flanking bases GG are recognized by Arg2 and His5. The residues involved in the E-box recognition are His5, Glu9 and Arg13, as already reported for bHLH/Zip proteins MAX and USF, and are different from those recognized by bHLH proteins MyoD and E47, although PHO4 is a bHLH protein.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Base Sequence
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Binding Sites / genetics
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Crystallography, X-Ray
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DNA, Fungal / chemistry
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DNA, Fungal / genetics
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DNA, Fungal / metabolism
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Electrochemistry
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Escherichia coli / genetics
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Helix-Loop-Helix Motifs
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Membrane Transport Proteins / chemistry*
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Membrane Transport Proteins / genetics
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Membrane Transport Proteins / metabolism
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Models, Molecular
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Molecular Sequence Data
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Molecular Structure
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Nucleic Acid Conformation
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Phosphate Transport Proteins*
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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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Saccharomyces cerevisiae / enzymology
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Saccharomyces cerevisiae / genetics
Substances
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DNA, Fungal
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Membrane Transport Proteins
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Phosphate Transport Proteins
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Recombinant Proteins
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phosphate permease