Ohki S Y, Yazawa M, Yagi K, Hikichi K
Department of Polymer Science, Faculty of Science, Hokkaido University.
J Biochem. 1991 Nov;110(5):737-42. doi: 10.1093/oxfordjournals.jbchem.a123650.
The interaction between calmodulin and mastoparan at various concentrations of calcium ions was studied by 1H NMR. It was found that at lower mastoparan concentrations 1 mol of mastoparan binds to both the C-terminal-half and N-terminal-half regions of calcium-saturated calmodulin. The mastoparan affinity is much greater for the C-terminal-half region than for the N-terminal-half region. At higher mastoparan concentrations, a further 1 mol of mastoparan binds to the N-terminal-region of calcium saturated calmodulin. The results can be interpreted in terms of the assumption that the N-terminal-half region of calmodulin with mastoparan has a higher calcium ion affinity than the C-terminal-half region without mastoparan. It is suggested that calcium ions transfer from the C-terminal-half region of calmodulin without mastoparan to the N-terminal-half region of calmodulin with mastoparan. This calcium ion transfer is discussed from the viewpoint of enzyme activation by calmodulin.
通过1H NMR研究了在不同钙离子浓度下钙调蛋白与蜂毒肽之间的相互作用。结果发现，在较低的蜂毒肽浓度下，1摩尔蜂毒肽与钙饱和钙调蛋白的C端半区和N端半区均结合。蜂毒肽对C端半区的亲和力远大于对N端半区的亲和力。在较高的蜂毒肽浓度下，又有1摩尔蜂毒肽与钙饱和钙调蛋白的N端区域结合。这些结果可以根据以下假设来解释：与蜂毒肽结合的钙调蛋白N端半区比未与蜂毒肽结合的C端半区具有更高的钙离子亲和力。有人提出，钙离子从未与蜂毒肽结合的钙调蛋白C端半区转移到与蜂毒肽结合的钙调蛋白N端半区。从钙调蛋白激活酶的角度讨论了这种钙离子转移。
