title: 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)(6)GG 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. Structural constraints evidenced on the free core-SRF are released in the wild-type complex and environmental heterogeneities appear in the vicinity of Tyr residues, due to higher water molecule access. The H-bonding configuration of one Tyr OH-group, in average, changes with a net transfer from H-bond acceptor character to a combined donor and acceptor character. A charge repartition distributed on both core-SRF and targeted SRE stabilizes the specific complex, allowing the two partners to experience a variety of conformations.
authors.affiliation: Laboratoire Acides Nucléiques & Biophotonique, FRE CNRS 3207, Université Pierre et Marie Curie, 5 rue Henri Desbruères, 91030 Evry, France.
authors.forename: Josef
authors.initials: J
authors.lastname: Stepánek
authors.forename: Vladimír
authors.initials: V
authors.lastname: Kopecký
authors.forename: Alberto
authors.initials: A
authors.lastname: Mezzetti
authors.forename: Pierre-Yves
authors.initials: PY
authors.lastname: Turpin
authors.forename: Denise
authors.initials: D
authors.lastname: Paulin
authors.forename: Bernard
authors.initials: B
authors.lastname: Alpert
authors.forename: Christian
authors.initials: C
authors.lastname: Zentz
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005786:Gene Expression Regulation; D006801:Humans; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D011487:Protein Conformation; D017434:Protein Structure, Tertiary; D027602:Serum Response Element; D026362:Serum Response Factor / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D013059:Spectrum Analysis, Raman; D014158:Transcription, Genetic; D014443:Tyrosine / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D026362:Serum Response Factor; D014443:Tyrosine