Loop energy in DNA.
Loop energy in DNA.
复制标题
DNA 中的循环能量。
DOI：
10.1002/bip.360261204
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发表时间：
1987
期刊：
影响因子：
2.9
通讯作者：
Delcourt,SG
中科院分区：
文献类型：
--
作者：
Blake,RD;Delcourt,SG
The loop function ƒ(N), representing the statistical weight ofNcomplementary residues in a closed ring, has been determined by analysis of high‐resolution melting curves of a series of recombinant homopoly(A · T)Ninserts in pBR322 DNA, where 150 >N> 50 base pairs (bp). Loops are found more stable and therefore presumably less elastic than expected for an ideal, freely jointed chain. A value of 97 ± 2 bp is obtained for the empirical orientation‐stiffness parameterDin the expression for nonideal chains, ƒ(N) = (N+D)−1.7. The 10% increase in apparent stiffness over that of an ideal chain closely coincides with the extent of residual stacking in the loop. It is thus concluded that the more favorable loop energy, such as expected of smaller loops, is due to the incipient helical orientation of some residues, predisposing the loop to reclosure. A quantitative loop function is essential for the prediction and assignment of domains in DNA.
