Effect of magnesium ions and temperature on the sequence-dependent curvature of DNA restriction fragments.
Effect of magnesium ions and temperature on the sequence-dependent curvature of DNA restriction fragments.
复制标题
镁离子和温度对 DNA 限制性片段的序列依赖性曲率的影响。
DOI：
10.1088/0953-8984/22/49/494110
复制
发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Lu,Yongjun
中科院分区：
文献类型：
--
作者：
Stellwagen,NancyC;Lu,Yongjun
瞬时电双折射已被用来量化的曲率的两个DNA限制性片段，一个199碱基对的片段从复制的M13噬菌体和207碱基对的片段从SV 40微型染色体中的VP 1基因的起点。SV 40和M13限制性片段中的稳定曲率是由于一系列紧密间隔的A片段，位于每个片段中心附近的40或60个碱基对“曲率模块”内的4-6个连续腺嘌呤残基的运行。M13和SV 40限制性片段在含有一价阳离子的溶液中表现出α 45的弯曲，在含有Mg 2+离子的溶液中表现出α 60的弯曲。曲率不是局限于一个单一的网站，但分布在不同的A道的曲率模块。热变性研究表明，在M13和SV 40限制性片段中的曲率在含有单价阳离子的溶液中直到30 ℃保持恒定，在含有Mg 2+离子的溶液中直到40 ℃保持恒定，然后开始随着温度的升高而缓慢降低。因此，这些DNA限制性片段中的稳定曲率存在于生物学上重要的温度37 ℃。
Transient electric birefringence has been used to quantify the curvature of two DNA restriction fragments, a 199-base-pair fragment taken from the origin of replication of the M13 bacteriophage and a 207-base-pair fragment taken from the VP1 gene in the SV40 minichromosome. Stable curvature in the SV40 and M13 restriction fragments is due to a series of closely spaced A tracts, runs of 4–6 contiguous adenine residues located within 40 or 60 base pair'curvature modules' near the center of each fragment. The M13 and SV40 restriction fragments exhibit bends of∼ 45 in solutions containing monovalent cations and∼ 60 in solutions containing Mg 2+ ions. The curvature is not localized at a single site but is distributed over the various A tracts in the curvature modules. Thermal denaturation studies indicate that the curvature in the M13 and SV40 restriction fragments remains constant up to 30 C in solutions containing monovalent cations, and up to 40 C in solutions containing Mg 2+ ions, before beginning to decrease slowly with increasing temperature. Hence, stable curvature in these DNA restriction fragments exists at the biologically important temperature of 37 C.