The DNA-binding domain of Drosophila melanogaster c-Myb undergoes a multistate denaturation.
The DNA-binding domain of Drosophila c-Myb protein has been studied using different spectroscopic probes, namely CD, fluorescence, acrylamide quenching and NMR, to determine the structure of some of its sub-domains and their relative stabilities in aqueous solutions. While CD and fluorescence spectroscopy showed that the protein had completely lost its tertiary and secondary structures in approximately 3 M urea, solvent accessibility of the tryptophan residues was still partial, as determined by acrylamide quenching. This suggested the presence of significant amounts of residual structure which persisted until the urea concentration was raised to approximately 6.0 M. Thermal-denaturation experiments also indicated the presence of an intermediate in the unfolding pathway. The experimental data could be fitted assuming a minimum of three states in both modes of denaturation. The thermodynamic parameters for the apparent three-state transition have been determined. From the protein stability curve, we have determined that Drosophila melanogaster Myb R123 has maximal stability at 16 degrees C and pH 7.0.
Madan
A
A
Tata Institute of Fundamental Research, Bombay, India.
Radha
P K
PK
Srivastava
A
A
Padhy
L C
LC
Hosur
R V
RV
D000818:Animals; D001665:Binding Sites; D002942:Circular Dichroism; D004268:DNA-Binding Proteins / Q000737:chemistry*; D004331:Drosophila melanogaster / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D011489:Protein Denaturation; D017510:Protein Folding; D011518:Proto-Oncogene Proteins / Q000737:chemistry*; D020598:Proto-Oncogene Proteins c-myb; D013050:Spectrometry, Fluorescence; D013696:Temperature; D013816:Thermodynamics; D014508:Urea / Q000737:chemistry
D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D020598:Proto-Oncogene Proteins c-myb; D014508:Urea