通过核磁共振光谱法阐明棘阿米巴肌动蛋白结合蛋白I中的聚-L-脯氨酸结合位点。

Elucidation of the poly-L-proline binding site in Acanthamoeba profilin I by NMR spectroscopy.

作者信息

Archer S J, Vinson V K, Pollard T D, Torchia D A

机构信息

Bone Research Branch, National Institute of Dental Research, National Institutes of Health, Bethesda, MD 20892.

出版信息

FEBS Lett. 1994 Jan 10;337(2):145-51. doi: 10.1016/0014-5793(94)80262-9.

DOI:10.1016/0014-5793(94)80262-9

PMID:8287969

Abstract

The multifunctional protein profilin is one of the most abundant proteins in the cytoplasm and is thought to regulate actin assembly and the phosphoinositide signaling pathway. Profilin binds to several different ligands including actin, poly-L-proline, and the head groups of polyphosphoinositides. Knowledge of profilin/ligand interactions is important for understanding the physiology of profilin in the cell. As a first step in the characterization of profilin/ligand complexes, we have studied a profilin/poly-L-proline complex in solution using high resolution NMR spectroscopy. Analysis of profilin NOE's and chemical shift data indicates that the protein secondary structure is conserved upon binding to poly-L-proline and that the binding site is located between the N- and C-terminal helices in a region rich in highly conserved aromatic sidechains. This site is adjacent to the proposed binding site for actin. In addition, the rate constant for dissociation of the complex is found to be 1.6 +/- 0.2 x 10(4) s-1.

摘要

多功能蛋白丝切蛋白是细胞质中含量最丰富的蛋白质之一，被认为可调节肌动蛋白组装和磷酸肌醇信号通路。丝切蛋白可与多种不同配体结合，包括肌动蛋白、聚-L-脯氨酸和多磷酸肌醇的头部基团。了解丝切蛋白/配体相互作用对于理解丝切蛋白在细胞中的生理学功能很重要。作为表征丝切蛋白/配体复合物的第一步，我们使用高分辨率核磁共振光谱研究了溶液中的丝切蛋白/聚-L-脯氨酸复合物。对丝切蛋白核Overhauser效应（NOE）和化学位移数据的分析表明，该蛋白的二级结构在与聚-L-脯氨酸结合后保持不变，且结合位点位于N端和C端螺旋之间富含高度保守芳香族侧链的区域。该位点与推测的肌动蛋白结合位点相邻。此外，发现复合物的解离速率常数为1.6±0.2×10⁴ s⁻¹。