1XUE

STRUCTURE OF GTGGAATGCAATGGAAC HAIRPIN, NMR, 10 STRUCTURES

Summary for 1XUE

• Entry DOI: 10.2210/pdb1xue/pdb
• Descriptor: DNA (5'-D(*GP*TP*GP*GP*AP*AP*TP*GP*CP*AP*AP*TP*GP*GP*AP*AP*C)-3') (1 entity in total)
• Functional Keywords: deoxyribonucleic acid, mutation, folding, centromere, satellite iii, dna
• Total number of polymer chains: 1
• Total formula weight: 5300.46

Authors

Zhu, L.,Chou, S.-H.,Reid, B.R. (deposition date: 1996-08-26, release date: 1997-03-12, Last modification date: 2024-05-22)

Primary citation

Zhu, L.,Chou, S.H.,Reid, B.R.
A single G-to-C change causes human centromere TGGAA repeats to fold back into hairpins.
Proc.Natl.Acad.Sci.USA, 93:12159-12164, 1996

PubMed Abstract: Recently, we established that satellite III (TGGAA)n tandem repeats, which occur at the centromeres of human chromosomes, pair with themselves to form an unusual "self-complementary" antiparallel duplex containing (GGA)2 motifs in which two unpaired guanines from opposite strands intercalate between sheared G.A base pairs. In separate studies, we have also established that the GCA triplet does not form bimolecular (GCA)2 motifs but instead promotes the formation of hairpins containing a GCA-turn motif in which the loop contains a single cytidine closed by a sheared G.A pair. Since TGCAA is the most frequent variant of TGGAA found in satellite III repeats, we reasoned that the potential of this variant to form GCA-turn miniloop fold-back structures might be an important factor in modulating the local structure in natural (TGGAA)n repeats. We report here the NMR-derived solution structure of the heptadecadeoxynucleotide (G)TGGAATGCAATGGAA(C) in which a central TGCAA pentamer is flanked by two TGGAA pentamers. This 17-mer forms a rather unusual and very stable hairpin structure containing eight base pairs in the stem, only four of which are Watson-Crick pairs, and a loop consisting of a single cytidine residue. The stem contains a (GGA)2 motif with intercalative 14G/4G stacking between two sheared G.A base pairs; the loop end of the stem consists of a sheared 8G.10A closing pair with the cytosine base of the 9C loop stacked on 8G. The remarkable stability of this unusual hairpin structure (Tm = 63 degrees C) suggests that it probably plays an important role in modulating the folding of satellite III (TGGAA)n repeats at the centromere.

PubMed: 8901550
DOI: 10.1073/pnas.93.22.12159

Experimental method

SOLUTION NMR