Bazari W L, Clarke M
J Biol Chem. 1981 Apr 10;256(7):3598-603.
We have purified calmodulin from the eukaryotic microorganism Dictyostelium discoideum (Clarke, M., Bazari, W. L., and Kayman, S. C. (1980) J. Bacteriol. 141, 397-400) and have compared it to calmodulin purified from bovine brain. The two proteins behaved almost identically during fractionation on ion exchange and gel filtration columns and on isoelectric focusing gels. Dictyostelium calmodulin had one-third the specific activity of brain calmodulin in the Ca2+-dependent activation of brain cyclic nucleotide phosphodiesterase; this activation was inhibited for both proteins by 25 microM trifluoperazine. Dictyostelium calmodulin also activated erythrocyte (Ca2+ + Mg2+)-ATPase and interacted with the inhibitory subunit of skeletal muscle troponin. Competition radioimmune assays showed that Dictyostelium calmodulin could compete with brain calmodulin for antibodies to brain calmodulin. These similarities indicate a close relationship between Dictyostelium and brain calmodulin and suggest that the functional capabilities of the protein have been conserved even among evolutionarily distant species. However, substantial differences in primary structure were detected by amino acid analyses and peptide mapping. Most interesting is the lack of trimethyllysine in Dictyostelium calmodulin. This unusual amino acid, which is commonly found in calmodulins, is therefore not essential for interaction between calmodulin and the calmodulin-regulated proteins tested here.
我们从真核微生物盘基网柄菌中纯化了钙调蛋白（克拉克，M.，巴扎里，W. L.，和凯曼，S. C.（1980年）《细菌学杂志》141卷，397 - 400页），并将其与从牛脑中纯化的钙调蛋白进行了比较。在离子交换柱、凝胶过滤柱以及等电聚焦凝胶上进行分级分离时，这两种蛋白质的行为几乎相同。在脑环核苷酸磷酸二酯酶的Ca²⁺依赖性激活过程中，盘基网柄菌钙调蛋白的比活性是脑钙调蛋白的三分之一；25微摩尔三氟拉嗪对这两种蛋白质的这种激活作用均有抑制。盘基网柄菌钙调蛋白还能激活红细胞（Ca²⁺ + Mg²⁺） - ATP酶，并与骨骼肌肌钙蛋白的抑制亚基相互作用。竞争放射免疫分析表明，盘基网柄菌钙调蛋白能与脑钙调蛋白竞争针对脑钙调蛋白的抗体。这些相似之处表明盘基网柄菌钙调蛋白与脑钙调蛋白之间关系密切，并表明即使在进化距离较远的物种中，该蛋白质的功能能力也得以保留。然而，通过氨基酸分析和肽图谱分析检测到一级结构存在显著差异。最有趣的是盘基网柄菌钙调蛋白中缺乏三甲基赖氨酸。因此，这种在钙调蛋白中常见的不寻常氨基酸，对于钙调蛋白与本文所测试的钙调蛋白调节蛋白之间的相互作用并非必不可少。
