STRUCTURE/INTERACTIONS OF ACTINS AND ACTIN-BINDING PROTEIN

Profilin是隔离肌动蛋白单体的小蛋白的原型。 最近，许多已演示或推定的分析器新功能已经 出现了。对苍蝇和酵母菌的遗传实验证实了 肌动蛋白细胞骨架中的Profilin功能。生化研究 提示Profilin作为磷脂酰肌醇的一个组成部分具有双重作用 信号转导机制和作为从膜到肌动蛋白的信使 和其他配体。此外，结合多-L-脯氨酸的能力是一种 侧写中的共同特征。该系统也是测试 基于结构的热力学分析(SBTA)模型是由Freire和 其他。该模型预测了描述的热力学参数 仅利用掩埋的极性和非极性的变化来折叠/去折叠蛋白质 区域作为特定于结构的信息。DeltaH、Delta S和DeltaG for 定量预测了血管紧张素II与抗体的结合 通过这种模式。我们计划通过使用它来探索它的有效性范围 分析富含Pro的多肽与Profilin的结合。因此，我们建议 致： 青霉Profilin I的核磁共振和X-射线结构提纯及比较 棘阿米巴。 棘阿米巴和脊椎动物Profilin的结构比较 用于系统发育分析。 鉴定与细胞结合的高亲和力Pro-Rick肽和蛋白质 利用基于结构的荧光技术研究Profilin上的多聚脯氨酸结合位点 Profilin的衍生物和噬菌体展示方法，确定结构 通过核磁共振或结晶学对这些多肽与Profilin的络合物进行分析。 Profilin与多聚脯氨酸结合的能量学表征 富含脯氨酸的配体；确定测量值是否由 墨菲和弗莱尔的SBTA模型。 棘阿米巴Actophorin是肌动蛋白单体家族的一员。 结合/肌动蛋白细丝切断蛋白，包括肌动蛋白解聚 因子、凝集素、粘附素和去肌动蛋白。生理功能和 这些蛋白质的作用机制仍在研究中。至 为这些蛋白质的高级研究提供了结构基础，我们 建议： 通过MAD相变来完善和细化乙酰胆碱晶体结构 方法。 结晶并测定脊椎动物粘附素的结构以供比较 使用阿托帕林。 结晶阿托霍林与SADP-肌动蛋白的复合体。 通过肌动蛋白模型探讨肌动蛋白细丝断裂的机制 阿托帕林复合体。我们将尝试结晶一些肌动蛋白- 结合蛋白。

Profilin is the prototype of small proteins that sequester actin monomers. Recently a host of demonstrated or putative new functions for profilin have emerged. Genetic experiments on flies and yeast established a role for profilin in the function of the actin cytoskeleton. Biochemical studies suggest a dual role for profilin as a component of the phosphoinositide signal transduction machinery and as a messenger from the membrane to actin and other ligands. In addition, the ability to bind poly-L-proline is a common feature among profilins. This system is also ideal for testing the Structure-Based Thermodynamic Analysis (SBTA) model developed by Freire and others. This model predicts the thermodynamic parameters describing protein folding/unfolding using only the change in buried polar and apolar area as structure-specific information. The deltaH, delta S and deltaG for the binding of angiotensin II to an antibody were quantitatively predicted by this model. We plan to probe its range of validity by using it to analyze the binding of proline-rich peptides to profilin. We thus propose to: Refine and compare the NMR and x-ray structures of profilin I from Acanthamoeba. Compare the structures of Acanthamoeba and vertebrate profilin as a basis for phylogenetic analysis. Identify high affinity proline-rick peptides and proteins that bind to the polyproline binding site on profilin using a structure based fluorescent derivatives of profilin and phage display methods, determine the structure of the complex of these peptides with profilin by NMR or crystallography. Characterize the energetics of binding of profilin to polyproline and to the proline rich ligands; determine if the measured values are predicted by the SBTA model of murphy and Freire. Acanthamoeba actophorin is a member of a family of actin monomer binding/actin filament severing proteins that includes actin depolymerizing factor, destrin, cofilin, and depactin. The physiological functions and mechanisms of action of these proteins is still under investigations. To provide a structural basis for advanced studies of these proteins, we propose to: Complete and refine the actophorin crystal structure by the MAD phasing method. Crystalize and determine the structure of vertebrate cofilin for comparison with actophorin. Crystalize the complex of actophorin with SADP-actin. Explore the mechanism of actin-filament severing by modeling of the actin- actophorin complex. We will attempt to crystalize a number of actin- binding proteins.