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The Aspergillus nidulans transcription factor AlcR forms a stable complex with its half‐site DNA: a NMR study
Author(s) -
Cerdan Rachel,
Collin Delphine,
Lenouvel François,
Felenbok Béatrice,
Guittet Eric
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(97)00430-4
Subject(s) - aspergillus nidulans , dna , oligonucleotide , chemistry , binding site , stereochemistry , consensus sequence , dna binding site , dissociation constant , transcription factor , biochemistry , promoter , base sequence , gene , gene expression , receptor , mutant
The Aspergillus nidulans transcription factor AlcR is shown by NMR and gel retardation assay to form a stable complex with oligonucleotide sequences comprising the consensus half‐site 5′‐TGCGG‐3′. Apparent μ M dissociation constants are evaluated by both methods. The measured lifetime of the complex is 74±7 ms at 20°C with the following DNA sequence: 5′‐C1G2T3G4C5G6G7A8T9C10‐3′. The major chemical shift variations upon binding involve both the two adjacent GC pairs (G6 and G7) and, clearly, the AT pairs at both ends of the consensus sequence (T3 and A8), suggesting additional contacts of the protein with the DNA. This extensive and strong interaction with the half‐site is another example of the variability in contacts of the fungal DNA‐binding proteins containing Zn 2 Cys 6 domains with their consensus sites. It is the first demonstration that a binuclear cluster protein can bind to DNA as a monomer with strong affinity.