Seamon K B, Moore B W
J Biol Chem. 1980 Dec 25;255(24):11644-7.
A protein previously isolated from octopus optic lobe is shown to have the biochemical characteristics of a calmodulin-like protein. The amino acid composition of the octopus calmodulin is similar to that of another sea invertebrate calmodulin, from Renilla reniformis, in that both contain a single residue of tyrosine which distinguishes them from the vertebrate calmodulins which contain two tyrosines. The 1H NMR spectra of the octopus calmodulin and bovine brain calmodulin are compared in their apo- and calcium-saturated conformations. A comparison of these spectra indicates that the single tyrosine of the octopus calmodulin is in a structurally homologous position to tyrosine-138 of bovine brain calmodulin. 1H NMR and UV difference spectroscopy also demonstrate that the solution conformations of the apo- and calcium-saturated forms of octopus calmodulin are very similar to those of bovine brain calmodulin. It is concluded that both proteins undergo similar calcium-induced changes in tertiary structure, which result in near identical solution conformations.
一种先前从章鱼视叶中分离出的蛋白质显示出具有类钙调蛋白的生化特性。章鱼钙调蛋白的氨基酸组成与另一种海生无脊椎动物——海肾（Renilla reniformis）的钙调蛋白相似，二者都只含有一个酪氨酸残基，这使它们有别于含有两个酪氨酸的脊椎动物钙调蛋白。对章鱼钙调蛋白和牛脑钙调蛋白在脱辅基和钙饱和构象下的1H NMR谱进行了比较。这些谱图的比较表明，章鱼钙调蛋白的单个酪氨酸处于与牛脑钙调蛋白酪氨酸-138结构同源的位置。1H NMR和紫外差光谱也表明，章鱼钙调蛋白脱辅基形式和钙饱和形式的溶液构象与牛脑钙调蛋白的非常相似。得出的结论是，两种蛋白质在三级结构上都经历了类似的钙诱导变化，这导致了几乎相同的溶液构象。
