基础(拓扑)
碱基对
化学
结晶学
立体化学
物理
DNA
生物化学
数学
数学分析
作者
Arijit Maity,Fernaldo Richtia Winnerdy,Gang Chen,Anh Tuân Phan
出处
期刊:Biochemistry
[American Chemical Society]
日期:2021-03-22
卷期号:60 (14): 1097-1107
被引量:5
标识
DOI:10.1021/acs.biochem.0c00916
摘要
Aberrant expansion of the hexanucleotide GGGGCC (or G4C2) repeat in the human C9ORF72 gene is the most common genetic factor found behind amyotrophic lateral sclerosis and frontotemporal dementia. The hypothesized pathways, through which the repeat expansions contribute to the pathology, involve one or more secondary structural forms of the DNA and/or RNA sequences, such as G-quadruplexes, duplexes, and hairpins. Here, we study the structures of DNA and RNA duplexes formed by G4C2 repeats, which contain G(syn)·G(anti) base pairs flanked by either G·C or C·G base pairs. We show that duplexes formed by G4C2 repeats contain alternately two types of G·G pair contexts exhibiting different syn–anti base flipping dynamics (∼100 ms vs ∼2 ms for DNA and ∼50 ms vs ∼20 ms for RNA at 10 °C, respectively) depending on the flanking bases, with the slow-flipping G·G pairs being flanked by a guanine at the 5′-end and the fast-flipping G·G pairs being flanked by a cytosine at the 5′-end. Our findings on the structures and dynamics of G·G base pairs in DNA and RNA duplexes formed by G4C2 repeats provide a foundation for further studies of the functions and targeting of such biologically relevant motifs.
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