钙调蛋白与来自大脑的被膜小泡的相互作用。

Interactions of calmodulin with coated vesicles from brain.

作者信息

Linden C D, Dedman J R, Chafouleas J G, Means A R, Roth T F

出版信息

Proc Natl Acad Sci U S A. 1981 Jan;78(1):308-12. doi: 10.1073/pnas.78.1.308.

DOI:10.1073/pnas.78.1.308

PMID:6941248

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC319042/

Abstract

Coated vesicles purified in the presence of calcium are enriched approximately 7-fold in calmodulin content relative to standard preparations isolated in the absence of free calcium. Radioiodinated calmodulin binds specifically to coated vesicles in vitro. Binding is saturable (Kd, 10 nM) and calcium dependent. Half-maximal binding occurs at 2.4 microM free Ca2+ whereas up to 1.2 mM Mg2+ has no effect on binding. Troponin C, a protein homologous to calmodulin, competes with binding of 125I-labeled calmodulin with 1/30th the affinity of native calmodulin. Chromatography of 2 M urea-solubilized coated vesicles on a calmodulin-Sepharose column demonstrated a Ca2+-dependent interaction of coated vesicle proteins and calmodulin. The properties of calmodulin binding to coated vesicles are comparable to those of calmodulin activities in other systems.

摘要

在有钙存在的情况下纯化的包被囊泡，其钙调蛋白含量相对于在无游离钙条件下分离的标准制剂大约富集了7倍。放射性碘化钙调蛋白在体外能特异性结合包被囊泡。结合具有饱和性（解离常数Kd为10 nM）且依赖于钙。半数最大结合发生在游离Ca2+浓度为2.4 μM时，而高达1.2 mM的Mg2+对结合没有影响。肌钙蛋白C是一种与钙调蛋白同源的蛋白质，它与125I标记的钙调蛋白结合的竞争能力仅为天然钙调蛋白亲和力的1/30。用钙调蛋白琼脂糖柱对2 M尿素溶解的包被囊泡进行层析，结果表明包被囊泡蛋白与钙调蛋白存在Ca2+依赖性相互作用。钙调蛋白与包被囊泡结合的特性与它在其他系统中的活性特性相当。