Thermal stability of the DNA-binding domain of the Myb oncoprotein.


The DNA-binding domain of the c-myb protooncogene product consists of three homologous tandem repeats of 51-52 amino acids (denoted as R1, R2, and R3 from the N-terminal side). In order to analyze conformational and thermodynamic characteristics of the homologous repeats, we have examined the DNA-binding domain by circular dichroism (CD) and differential scanning calorimetry (DSC). The CD spectra for the three individual repeats are significantly different in the fine profiles, indicating subtle differences in their conformations. The melting analyses for the fragments show that the thermal stability of each fragment is different from one another, with the following order of stability: R1(Tm = 61 degrees C) approximately greater than R3(57 degrees C) > R2(43 degrees C), where R2 is much less stable than the other repeats. The denaturing process for the whole DNA-binding domain, measured by DSC, is characterized by a very broad transition ranging from 30 to 80 degrees C. The denaturation curve can be fit well by a three-state transition with one intermediate state. The transition temperature for the native-to-intermediate transition coincides with the melting temperature of R2, indicating that the intermediate state corresponds to the unfolding of unstable R2. The CD spectrum of the whole domain is almost identical to the sum of the individual spectra. Thus, these results suggest that the individual repeats in the whole DNA-binding domain behave independently in terms of conformation and stability. The addition of DNA to the DNA-binding fragment drastically changed the melting profile, in which the broad transition curve was replaced by a sharp peak at 58 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS) Study holds ProTherm entries: 2466, 2467 Extra Details: This transition is from native to intermediate states,,corresponding to the melting of R2. Myb; DNA binding domain; thermal stability; three-state transition

Submission Details

ID: PuhHn9X83

Submitter: Connie Wang

Submission Date: April 24, 2018, 8:19 p.m.

Version: 1

Publication Details
Sarai A;Uedaira H;Morii H;Yasukawa T;Ogata K;Nishimura Y;Ishii S,Biochemistry (1993) Thermal stability of the DNA-binding domain of the Myb oncoprotein. PMID:8347585
Additional Information

Structure view and single mutant data analysis

Study data

No weblogo for data of varying length.
Colors: D E R H K S T N Q A V I L M F Y W C G P

Data Distribution

Studies with similar sequences (approximate matches)

Correlation with other assays (exact sequence matches)

Relevant UniProtKB Entries

Percent Identity Matching Chains Protein Accession Entry Name
100.0 Transcriptional activator Myb P06876 MYB_MOUSE
100.0 Transcriptional activator Myb P10242 MYB_HUMAN
100.0 Transcriptional activator Myb P46200 MYB_BOVIN
100.0 Transcriptional activator Myb P01103 MYB_CHICK
98.1 Transcriptional activator Myb P52550 MYBA_CHICK
98.1 Transcriptional activator Myb P10243 MYBA_HUMAN
98.1 Transcriptional activator Myb P51960 MYBA_MOUSE
98.1 Transcriptional activator Myb Q08759 MYB_XENLA
90.4 Transcriptional activator Myb Q05935 MYBA_XENLA
94.2 Transcriptional activator Myb P01104 MYB_AVIMB