INVESTIGATING NOVEL DNA FLUORSCENCE LABELING PROBES

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。K. Burgess及其同事已经开发出几种不同类型的荧光探针，用于DNA标记，其中包含多个荧光发色团，它们具有不同的可见荧光光谱，但在同一波长具有相同的高吸收横截面。这类分子的两种类型包括试验系统，涉及具有强荧光基团的寡核苷酸偶联到核碱基（如胸腺嘧啶），以及结合到DNA中的刚性、偶联、荧光化胸腺嘧啶三磷酸。当前项目的目的是通过两种不同的方法直接测量能量传递动力学：荧光上转换（150 fs分辨率）和双光子诱导荧光技术（~100 fs分辨率）。最近与其他双发色团探针的比较，包括罗丹明和荧光素的衍生物，揭示了能量传递速率与两个发色团的电子跃迁矩的相对取向和连接它们的不饱和基团的轴的相关性。目前正在通过对每种发色团对的能量转移率和荧光各向异性的研究来检验这些相关性。

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. K. Burgess and co-workers have developed several different types of fluorescence probes for DNA labeling containing more than one fluorescent chromophore, which have distinct visible fluorescence spectra and yet have the same high absorption cross sections at a common wavelength. Two types of such molecules have included trial systems involving oligonucleotides with strongly fluorescent groups conjugated to a nucleobase such as thymidine, and rigid, conjugated, fluoresceinated thymidine triphosphates incorporated into DNA. The aim of the current project is to directly measure energy transfer dynamics by two distinct methods: fluorescence upconversion (150 fs resolution) and a two-photon induced fluorescence technique (~100 fs resolution). Recent comparisons with other dual chromophore probes, involving derivatives of rhodamine and fluorescein, have revealed a correlation of the energy transfer rate with the relative orientation of the electronic transition moments of the two chromophores and the axis of the unsaturated group connecting them. These correlations are currently being examined, through studies of both the energy transfer rate and the fluorescence anisotropy of each type of chromophore pair.