Stability of chimeric DNA/RNA cytosine tetrads: Implications for i-motif formation by RNA

被引:62
作者
Collin, D
Gehring, K
机构
[1] McGill Univ, Dept Biochem, Montreal, PQ H3G 1Y6, Canada
[2] McGill Univ, Montreal Joint Ctr Struct Biol, Montreal, PQ H3G 1Y6, Canada
[3] CNRS, Inst Chim Subst Nat, Lab Resonance Magnet Nucl, F-94128 Gif Sur Yvette, France
关键词
D O I
10.1021/ja973346r
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
UV melting curves of mono-and di-2'-hydroxylated cytosine tetrads were recorded. The substitution of one DNA residue by RNA decreased the melting temperature (T-m) by roughly 6.5 degrees C. In sequences with two RNA residues, strong positional effects were observed. Juxtaposition of the two D-ribose sugars in the tetrad incurred an additional loss of 6 degrees C in tetrad stability and decreased the T-m by 19 degrees C from that of the parent compound, d(TCCCCC)(4). The effect of increasing the number of cytosines on tetrad stability was also measured. Addition (or removal) of one cytosine-protonated cytosine base-pair from the tetrad increased (or decreased) the T-m by roughly; 9 degrees C. Thus, the penalty of adding an RNA residue is equal to or greater than the benefit of the additional base-pair. This implies that the stability of RNA cytosine-tetrads should not rise with increasing length and that thermal transitions previously observed in poly(rC) correspond to duplex structures.
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页码:4069 / 4072
页数:4
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