Analysis of the conformation and stability of rat TTF-1 homeodomain by circular dichroism.
The conformational stability of TTF-1HD has been determined by CD-monitored thermal denaturation and isothermal urea unfolding studies. The Gibbs free energy of stabilization found are 1.44 and 1.26 kcal.mol-1, respectively. TTF-1HD exhibits a Tm of 42 degrees C and a delta Cp of 80 cal.mol-1.K-1 indicating that TTF-1HD, when free in solution, is a mobile flexible segment folded into loose helices. Such a flexibility would be relevant for the DNA-binding function of this homeodomain. In fact, a small reduction of the alpha-helical content of TTF-1HD significantly modifies its DNA-binding activity.
Damante
G
G
Dipartimento di Scienze e Tecnologie Biomediche, Università degli Studi di Udine, Italy.
Tell
G
G
Leonardi
A
A
Fogolari
F
F
Bortolotti
N
N
Di Lauro
R
R
Formisano
S
S
D000818:Animals; D002942:Circular Dichroism; D004268:DNA-Binding Proteins / Q000737:chemistry*; D006358:Hot Temperature; D009687:Nuclear Proteins / Q000737:chemistry*; D011487:Protein Conformation; D011489:Protein Denaturation; D017433:Protein Structure, Secondary; D051381:Rats; D013816:Thermodynamics; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors / Q000737:chemistry*; D014508:Urea
D004268:DNA-Binding Proteins; C000614416:Nkx2-1 protein, rat; D009687:Nuclear Proteins; D000074482:Thyroid Nuclear Factor 1; D014157:Transcription Factors; D014508:Urea