Structural and dynamic changes of the serum response element and the core domain of serum response factor induced by their association
Abstract
Transcriptional activity of serum response factor (SRF) is dependent on its binding to the CC(A/T)6GG box (CArG box) of serum response element (SRE). By Raman spectroscopy, we carried out a comparative analysis, in solution, of the complexes obtained from the association of core-SRF with 20-mer SREs bearing wild-type and mutated c-fos CArG boxes.
In case of association with the wild type c-fos CArG box, the complex does not bring out the expected Raman signature of a stable bending of the targeted SRE but keeps a bend–linear conformer oligonucleotide interconversion. The linear conformer population is larger than that of free oligonucleotide.
In the core-SRF moiety of the wild-type complex a large spectral change associated with the CO-groups from Asp and/or Glu residues shows that their ionization states and the strength of their interactions decrease as compared to those of mutated non-specific complexes.