Watterson D M, Sharief F, Vanaman T C
J Biol Chem. 1980 Feb 10;255(3):962-75.
We present the data required to establish the complete amino acid sequence of bovine brain modulator protein, the multifunctional calcium-dependent regulatory protein. Bovine brain modulator protein contains 148 amino acid residues and has a molecular mass of 16,680 daltons. The protein commences with an acetylated alanyl residue in accord with the previous report that its NH2 terminus was blocked. The single residues of histidine and trimethyllysine occur at positions 107 and 115, respectively, in a region of the linear sequence implicated by other studies as important for calcium-dependent modulator protein-enzyme interactions. The sequence of bovine brain modulator protein demonstrated here is closely related to those of muscle troponin Cs, as originally suggested from considerations of the similarities in calcium binding and functional and physicochemical properties of these proteins (Watterson, D.M., Harrelson, W.G., Jr., Keller, P.M., Sharief, F., and Vanaman, T.C. (1976) J. Biol. chem. 251, 4501-4513). The linear amino acid sequence of bovine brain modulator protein is composed of four internally homologous sequences or domains, each of which contains the appropriate amino acids arranged so as to form a helix-loop-helix, calcium-binding structure. The high level of internal homology of bovine brain modulator protein and its relationship to the other members of the calcium-binding protein superfamily provide convincing evidence that 1) it arose early in the evolution of these related proteins and 2) it was formed by two successive tandem duplications of a gene encoding a small, single domain ancestral precursor. Comparison with the nearly complete sequences of the bovine uterus and rat testis modulator proteins reported by other laboratories indicates that this ubiquitous calcium-dependent regulatory protein does not occur in tissue-specific forms, commensurate with the proposed function of modulator protein as a mediator of calcium-second messenger function in eukaryotic cells.
我们展示了确定牛脑调节蛋白（一种多功能钙依赖性调节蛋白）完整氨基酸序列所需的数据。牛脑调节蛋白含有148个氨基酸残基，分子量为16,680道尔顿。该蛋白以乙酰化丙氨酰残基开始，这与之前关于其NH2末端被封闭的报道一致。组氨酸和三甲基赖氨酸的单个残基分别出现在第107和115位，在其他研究表明对钙依赖性调节蛋白与酶相互作用很重要的线性序列区域中。这里展示的牛脑调节蛋白序列与肌肉肌钙蛋白C的序列密切相关，这最初是从这些蛋白质在钙结合以及功能和物理化学性质方面的相似性考虑得出的（沃特森，D.M.，哈雷尔森，W.G.，Jr.，凯勒，P.M.，沙里夫，F.，和瓦纳曼，T.C.（1976年）《生物化学杂志》251，4501 - 4513）。牛脑调节蛋白的线性氨基酸序列由四个内部同源序列或结构域组成，每个结构域都包含适当排列的氨基酸，以形成螺旋 - 环 - 螺旋钙结合结构。牛脑调节蛋白的高度内部同源性及其与钙结合蛋白超家族其他成员的关系提供了令人信服的证据，即1）它在这些相关蛋白质的进化早期就出现了，2）它是由编码一个小的、单结构域祖先前体的基因的两次连续串联重复形成的。与其他实验室报道的牛子宫和大鼠睾丸调节蛋白的近乎完整序列进行比较表明，这种普遍存在的钙依赖性调节蛋白不存在组织特异性形式，这与调节蛋白作为真核细胞中钙第二信使功能介导者的拟议功能相符。
