Charbonneau H, Walsh K A, McCann R O, Prendergast F G, Cormier M J, Vanaman T C
Biochemistry. 1985 Nov 19;24(24):6762-71. doi: 10.1021/bi00345a006.
The Ca(II)-dependent photoprotein aequorin produces the luminescence of the marine coelenterate Aequorea victoria. The complete amino acid sequence of aequorin has been determined. A complete set of nonoverlapping peptides was produced by cyanogen bromide cleavage. These peptides were aligned by using the amino-terminal sequence of the intact protein and the sequences of selected arginyl and lysyl cleavage products. Although the aequorin preparations employed in these studies were homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the presence of a minimum of 3 isotypes was demonstrated by the location of 17 sites of sequence microheterogeneity. Two amino acid variants were observed at each of 16 positions while 1 position had 3 different replacements. The protein as isolated has 189 amino acids with an unblocked amino terminus. According to the sequence reported here, the molecular weight of the apoprotein is 21 459 while that of the holoprotein is 21 914. The molecule possesses three internally homologous domains which were judged to be EF-hand Ca(II) binding domains by several different criteria. Aequorin is homologous to troponin C and to calmodulin. These findings demonstrate that aequorin is a member of the Ca(II) binding protein superfamily.
依赖钙离子的光蛋白水母发光蛋白可产生海洋腔肠动物维多利亚多管水母的生物发光。水母发光蛋白完整的氨基酸序列已被确定。通过溴化氰裂解产生了一套完整的非重叠肽段。利用完整蛋白的氨基末端序列以及选定的精氨酰和赖氨酰裂解产物的序列，对这些肽段进行了比对。尽管这些研究中使用的水母发光蛋白制剂经十二烷基硫酸钠 - 聚丙烯酰胺凝胶电泳显示是均一的，但通过17个序列微异质性位点的定位证明至少存在3种同种型。在16个位置上每个位置观察到两种氨基酸变体，而1个位置有3种不同的替换。分离得到的该蛋白有189个氨基酸，氨基末端未封闭。根据此处报道的序列，脱辅基蛋白的分子量为21459，而全蛋白的分子量为21914。该分子具有三个内部同源结构域，通过几种不同标准判断它们为EF手型钙离子结合结构域。水母发光蛋白与肌钙蛋白C和钙调蛋白同源。这些发现表明水母发光蛋白是钙离子结合蛋白超家族的成员。
