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A parallel stranded G‐quadruplex composed of threose nucleic acid (TNA)
Author(s) -
Liao Jenyu,
Anosova Irina,
Bala Saikat,
Van Horn Wade D.,
Chaput John C.
Publication year - 2017
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.22999
Subject(s) - chemistry , g quadruplex , nucleic acid , circular dichroism , dna , structural motif , nuclear magnetic resonance spectroscopy , stereochemistry , crystallography , nucleic acid structure , rna , combinatorial chemistry , biochemistry , gene
Abstract G‐rich sequences can adopt four‐stranded helical structures, called G‐quadruplexes, that self‐assemble around monovalent cations like sodium (Na + ) and potassium (K + ). Whether similar structures can be formed from xeno‐nucleic acid (XNA) polymers with a shorter backbone repeat unit is an unanswered question with significant implications on the fold space of functional XNA polymers. Here, we examine the potential for TNA (α‐ l ‐threofuranosyl nucleic acid) to adopt a four‐stranded helical structure based on a planar G‐quartet motif. Using native polyacrylamide gel electrophoresis (PAGE), circular dichroism (CD) and solution‐state nuclear magnetic resonance (NMR) spectroscopy, we show that despite a backbone repeat unit that is one atom shorter than the backbone repeat unit found in DNA and RNA, TNA can self‐assemble into stable G‐quadruplex structures that are similar in thermal stability to equivalent DNA structures. However, unlike DNA, TNA does not appear to discriminate between Na + and K + ions, as G‐quadruplex structures form equally well in the presence of either ion. Together, these findings demonstrate that despite a shorter backbone repeat unit, TNA is capable of self‐assembling into stable G‐quadruplex structures.