PROTEIN PROTEIN & PROTEIN LIGAND INTERACTIONS

蛋白质溶液动力学的稳态和动态研究 时间分辨荧光方法研究蛋白质齐聚物的形成和 配基结合--两种蛋白质系统正在研究中：(1) Ras p21癌基因产物和(2)可溶性蛇毒(Akistrodon) 和磷脂酮A2s3。(1) Ras p21癌基因蛋白的寡聚体结构及局部定位 其鸟嘌呤核苷酸结合部位的构象动力学为 正在用荧光标记的核苷酸进行研究。两者都是全球性的 正在检查当地的环境参数，以确定 溶液低聚物的形成及其构象差异 在各种ras p21蛋白的GTP和GDP型之间以及 致癌突变体。荧光寿命和动力学 正在获取偏振数据。(2)溶液中的磷脂酶A2 从眼镜蛇毒液中分离出来的(PLA2)似乎聚集在配体上， 磷脂和/或钙离子，而响尾蛇毒液中的PLA2仍然是 胰腺中的二聚体和PLA2以单体形式存在。高度的 这些酶之间的序列相似性和作用模式表明 共同的机制。溶液的结构、配体对分子的影响 这种结构，以及低聚物与酶功能之间的联系 正在通过荧光能量转移和动力学研究 极化。

Investigation of Protein Solution Dynamics by Steady-State and Time- Resolved Fluorescence Methods Protein Oligomer Formation and Ligand Association--Two protein systems are being investigated: (1) the ras p2l oncogene products and (2) the soluble venom (Akistrodom piscovorous & Crotalus atrox) and phospholipone A2s3. (1) The oligomeric structure of the ras p2l oncogene proteins and the local conformational dynamics of their guanine nucleotide binding site is being investigated with fluorescently tagged nucleotides. Both global and local environmental parameters are being examined to define the solution oligomer form and the pertinent conformational differences between the GTP- and GDP-forms of the various ras p2l proteins and cancer-causing mutants. Fluorescence lifetimes and dynamic polarization data are being taken. (2) In solution phospholipase A2 (PLA2) isolated from Cobra venom appears to aggregate upon ligand, phospholipid and/or Ca++, while PLA2 from rattlesnake venom remains a dimer and PLA2 from pancreas exists as a monomer. The high degree of sequence similarity and modes of action among these enzymes suggests a common mechanism. The solution structure, the effect of ligands on this structure, and the link between the oligomer and enzyme function are being investigated by fluorescence energy transfer and dynamic polarization.