pH 值、温度和阳离子卟啉 TMPyP4 对人端粒 5'-(C3TA2)4-3' 序列形成的 i 型结构稳定性的影响。

Influence of pH, temperature and the cationic porphyrin TMPyP4 on the stability of the i-motif formed by the 5'-(C3TA2)4-3' sequence of the human telomere.

机构信息

Solution Equilibria and Chemometrics group (Associate Unit UB-CSIC), Department of Analytical Chemistry, University of Barcelona, Barcelona, Spain.

出版信息

Int J Biol Macromol. 2011 Nov 1;49(4):729-36. doi: 10.1016/j.ijbiomac.2011.07.004. Epub 2011 Jul 12.

DOI:10.1016/j.ijbiomac.2011.07.004

PMID:21777611

Abstract

The influence of pH, temperature and the cationic porphyrin TMPyP4 on the conformational equilibria of the cytosine-rich strand of the human telomeric sequence 5'-(C(3)TA(2))(4)-3', as well as those of the sequence 5'-(C(3)TT(2))(4)-3', was studied. The presence of adenine bases at the loops causes the formation of two different intramolecular i-motif structures with a pH-transition midpoint around 4.6, which stability is lower than the i-motif formed by the sequence 5'-(C(3)TT(2))(4)-3'. The stoichiometries of the complexes formed by these i-motif structures with TMPyP4 are also influenced by the presence of adenine at the loops.

摘要

研究了 pH 值、温度以及阳离子卟啉 TMPyP4 对富含胞嘧啶的人端粒序列 5'-(C(3)TA(2))(4)-3'的构象平衡，以及序列 5'-(C(3)TT(2))(4)-3'的构象平衡的影响。环处的腺嘌呤碱基的存在导致形成两种不同的分子内 i- 型结构，其 pH 转变中点约为 4.6，其稳定性低于由序列 5'-(C(3)TT(2))(4)-3'形成的 i- 型结构。这些 i- 型结构与 TMPyP4 形成的配合物的化学计量也受到环处腺嘌呤存在的影响。