Light Scattering Studies of DNA Dynamics

水离子环境影响DNA分子之间的远程分子间相互作用，DNA分子线圈的膨胀或冷凝程度以及短程螺旋结构。在这些领域中，有一些惊人的转变，在现有的多电解质理论或核酸化学的基础上还没有被清楚地理解。布卢姆菲尔德博士的目标是了解促成这些转变的力量。应用的技术有动态激光散射、小角x射线和中子散射、紫外可见、CD和激光拉曼光谱以及化学探针。理论技术也将被使用。DNA经历了一些惊人的相变。所有这些转变在很大程度上取决于离子强度以及其他变量，如聚合物浓度、分子量、温度和特定离子效应。迄今为止，分子生物学主要研究的是编码型数据。然而，在更高的层次上，所使用的代码（即DNA）的选择具有内置的控制机制，人们普遍认为，这种机制部分涉及到其他控制分子与DNA的结合，部分涉及到DNA构象的改变。了解dna可能相互作用的方式必须先于对控制机制的某些类型的理解，这里提出的实验正是处理这个问题

The aqueous ionic milieu influences long-range intermolecular interactions between DNA molecules, the degree of expansion or condensation of the DNA molecular coil and the short range helical structure. Within each of these domains, there are striking transitions not yet clearly understood on the basis of existing polyelectrolyte theory or nucleic acid chemistry. Dr. Bloomfield's goal is to understand the forces mediating these transitions. Some of the techniques to be used are dynamic laser scattering, small angle X-ray and neutron scattering, UV-visible, CD and laser Raman spectroscopy and chemical probes. Theoretical techniques will also be used. DNA undergoes some striking phase changes. All of these transitions depend strongly on ionic strength as well as on other variables such as polymer concentration, molecular weight, temperature and specific ion effects. Molecular biology has thus far concerned itself primarily with coding- type data. However, at a higher level, the choice of a code which is used (i.e., the DNA) has control mechanisms built into it which are widely believed to involve in part, binding of other control molecules to the DNA, and in part, changes in the DNA conformation. Knowledge of ways in which DNAs are likely to interact must precede some types of understanding of control mechanisms and the experiments proposed here treat precisely this problem.***//