Cystosine-rich strands of the insulin minisatellite adopt hairpins with intercalated cytosine+.cytosine pairs.
J Mol Biol
; 272(3): 369-82, 1997 Sep 26.
Article
de En
| MEDLINE
| ID: mdl-9325097
ABSTRACT
Previously, we reported the high resolution NMR structure of the hairpin G-quartet structure formed by the G-rich strand of the insulin minisatellite of repeat sequence, (ACAG4TGTG4/TGTC4ACAC4) located upstream of the human insulin gene. Here, we report structural studies on the C-rich strand of this insulin minisatellite. First, we show by high resolution NMR that (C4TGTC4) forms a hairpin dimer with intercalated C+.C pairs (referred to as the hairpin i-motif); 340 NOE distance constraints uniquely define the nature of hairpin folding and the pattern of C+.C intercalation. Second, we show by one-dimensional NMR spectroscopy and molecular modeling studies that (C4TGTC4ACA4TGTC4) forms an intramolecularly folded hairpin with intercalated C+.C pairs. Third, we demonstrate by in vitro replication studies that several such hairpin i-motifs are present in long (C4TGTC4ACA)n (n>/=6) sequences, even in the presence of their complementary strands. Finally, we discuss structural and biological significance of the hairpin i-motifs formed by the C-rich strands of the insulin minisatellite.
Recherche sur Google
Collection:
01-internacional
Base de données:
MEDLINE
Sujet principal:
Oligodésoxyribonucléotides
/
Répétitions minisatellites
/
Cytosine
/
Insuline
/
Conformation d'acide nucléique
Type d'étude:
Prognostic_studies
Limites:
Humans
Langue:
En
Journal:
J Mol Biol
Année:
1997
Type de document:
Article
Pays d'affiliation:
États-Unis d'Amérique