Effect of salt concentration on TTF-1 HD binding to specific and non-specific DNA sequences.
The Thyroid Transcription factor 1 (TTF-1) recognizes specific DNA sequences by a Homeodomain (TTF-1 HD). The TTF-1 HD DNA-binding properties with both specific and non-specific DNA sequences were investigated. TTF-1 HD exists as a monomer in solution and as a monomer binds DNA. At 75 mM KCl, its relative binding affinity with a specific DNA sequence is about 50 fold higher than with a non-specific DNA sequence. Increase of KCl concentration reduces the apparent binding affinity both to specific and non-specific DNA sequences. However, non-specific binding is more sensitive than specific binding to the increase of salt concentration. When DNA-binding reactions are performed at temperature and salt concentration close to the intracellular environment, TTF-1 HD binds the specific sequence with an affinity at least 1000 fold higher respect to the non-specific sequence.
Damante
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Dipartimento di Scienze e Tecnologie Biomediche Università di Udine, Italy.
Tell
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Formisano
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Fabbro
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D
Pellizzari
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Di Lauro
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R
D000818:Animals; D001483:Base Sequence; D001665:Binding Sites; D002417:Cattle; D002850:Chromatography, Gel; D003001:Cloning, Molecular; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D007700:Kinetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*; D009838:Oligodeoxyribonucleotides; D009994:Osmolar Concentration; D011189:Potassium Chloride / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism; D013816:Thermodynamics; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000096:biosynthesis / Q000302:isolation & purification / Q000378:metabolism*
D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009838:Oligodeoxyribonucleotides; D011994:Recombinant Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D011189:Potassium Chloride; D004247:DNA