6J37

DNA minidumbbell structure of two CTTG repeats

6J37 の概要

• エントリーDOI: 10.2210/pdb6j37/pdb
• 分子名称: DNA (5'-D(*CP*TP*TP*GP*CP*TP*TP*G)-3'), SODIUM ION (2 entities in total)
• 機能のキーワード: minidumbbell, reverse wobble tt mispair, hydrophobic interaction, dna
• 由来する生物種: Homo sapiens
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 2569.52

構造登録者

Lam, S.L.,Guo, P. (登録日: 2019-01-04, 公開日: 2019-05-29, 最終更新日: 2024-05-01)

主引用文献

Guo, P.,Lam, S.L.
Unprecedented hydrophobic stabilizations from a reverse wobble T·T mispair in DNA minidumbbell.
J.Biomol.Struct.Dyn., 38:1946-1953, 2020

PubMed Abstract: Minidumbbell (MDB) is a newly found non-B DNA structure formed by short single-strand sequences. Up to now, three MDBs have been reported to form at neutral pH by sequences containing two repeats of TTTA, CCTG and CTTG. Among them, the thermodynamically less stable TTTA and CCTG MDBs have been proposed to be the structural intermediates that cause TTTA and CCTG repeat expansions during DNA replication in pathogen and myotonic dystrophy type 2 patients, respectively. Although the CTTG MDB has a melting temperature of at least 13 °C higher than those of the other two, no CTTG repeat expansion has ever been reported in any genomes. In this study, we successfully determined the solution structure of the CTTG MDB and observed for the first time the formation of a reverse wobble T·T mispair with two symmetric hydrogen bonds. More importantly, we identified unprecedented hydrophobic interactions between the two methyl groups of this T·T mispair and the four 2'-methylene groups of their nearby loop-closing base pair residues. These stabilizations account for the substantial increase in the MDB thermodynamic stability which may govern the occurrence of repeat expansions.Communicated by Ramaswamy H. Sarma [Formula: see text].

PubMed: 31107180
DOI: 10.1080/07391102.2019.1621211

実験手法

SOLUTION NMR