Data di Pubblicazione:
1999
Citazione:
NF-Y binding to twin CCAAT boxes : role of Q-rich domains and histone fold helices / C. Liberati, A. di Silvio, S. Ottolenghi, R. Mantovani. - In: JOURNAL OF MOLECULAR BIOLOGY. - ISSN 0022-2836. - 285:4(1999 Jan 29), pp. 1441-1455.
Abstract:
NF-Y (CBF) is a CCAAT-binding trimer that activates 25% of eukaryotic promoters. It contains putative histone fold motifs (HFMs) and distorts DNA. By using electrophoretic mobility shift assays with the twin CCAAT boxes of the human γ-globin promoter and several combinations of subunit mutants, we dissected some of the structural features of CCAAT-box binding. NF-YA and NF-YC Q-rich domains significantly influence bending angles quantitatively, but not qualitatively, since they do not modify DNA orientation. They are both required for co-operative interactions among NF-Y molecules: for this, a precise alignement of two CCAAT boxes, 32 bp, three turns of the helix, is essential. Unlike the wild-type (wt) protein, steric hindrance does not impede simultaneous binding of the mutant composed of the short homology domains to CCAAT boxes closer than 22 bp: the addition of 11 amino acid residues to NF-YB and 13 to NF-YC flanking the HFM, restores wt behaviour. These stretches are predicted to form H2B-like αC and H2A-like αN fourth helices. A further support to this hypothesis comes from off-rates analysis of mutant combinations: the half-life of NF-Y, which is dependent on the type of NF-YB used, is extremely shortened, when the putative αC is present, nearly as much as in the wt NF-YB. These data (i) provide further evidence that NF-YB-NF-YC belong to the H2B-H2A subclasses, (ii) uncover new features of Q-rich domains, and (iii) define rules for NF-Y synergy that are potentially important for the regulation of many eukaryotic promoters.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Amino Acid Sequence ; Base Sequence ; Binding Sites ; CCAAT-Enhancer-Binding Proteins ; DNA ; DNA-Binding Proteins ; Globins ; Histones ; Humans ; Kinetics ; Molecular Sequence Data ; Mutation ; Promoter Regions, Genetic ; Protein Conformation ; Protein Folding ; Protein Structure, Secondary
Elenco autori:
C. Liberati, A. di Silvio, S. Ottolenghi, R. Mantovani
Link alla scheda completa: