REMEASURING THE DOUBLE HELIX

重新测量双螺旋

• 批准号: 8170216
• 负责人: Rebecca S. Fenn
• 金额: $ 0.17万
• 依托单位: STANFORD UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-01 至 2011-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8170216
• 关键词: Computer Retrieval of Information on Scientific Projects Database; DNA; Funding; Gold; Grant; Institution; Ionic Strengths; Label; Length; Measurement; Measures; Published Comment; Research; Research Personnel; Resources; Science; Series; Sodium Chloride; Solutions; Source; Stretching; Testing; United States National Institutes of Health; nanocrystal; response; trend

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. We recently measured the mean and variance of end-to-end length for a series of DNA double helices in solution, using small-angle x-ray scattering interference between gold nanocrystal labels. The observed variance in end-to-end length increases dramatically as a function of length. We have attributed this increase in variance to a soft stretching mode. Two technical comments have been submitted to Science; the authors suggest that the increase in observed variance as a function of length can be attributed to bending of the DNA. One way to test this hypothesis is to change the persistence length by modulating ionic strength and valence. If bending can explain the observed trend, measurements at either low ionic strength (10 mM Na+) or with a multivalent salt (putrescine2+) will decrease the persistence length and increase the variance. In order to prepare our response to the technical comment(s), we must make these measurements as soon as possible and establish the contribution of bending to our observed variances.

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 最近，我们测量了一系列DNA双螺旋在溶液中的端到端长度的平均值和方差，使用小角度X射线散射干涉之间的金纳米标记。观察到的端到端长度的变化作为长度的函数急剧增加。我们将方差的增加归因于软拉伸模式。两个技术评论已经提交给科学;作者认为，观察到的变化作为长度的函数的增加可以归因于DNA的弯曲。检验这一假设的一种方法是通过调节离子强度和化合价来改变持久长度。如果弯曲可以解释观察到的趋势，在低离子强度（10 mM Na+）或多价盐（腐胺2+）的测量将减少持久性长度和增加方差。为了准备我们对技术评论的回应，我们必须尽快进行这些测量，并确定弯曲对我们观察到的差异的贡献。