Offner G D, Troxler R F
J Biol Chem. 1983 Aug 25;258(16):9931-40.
The complete amino acid sequences of the alpha and beta subunits of allophycocyanin from the unicellular rhodophyte, Cyanidium caldarium, were determined by automated Edman degradation of the proteins and peptides derived from them by chemical and enzymatic cleavages. The sequence of the alpha subunit was determined from the sequences of tryptic, endoproteinase lysine-C, and cyanogen bromide peptides and carboxypeptidase A and Y digestion of the protein. The sequence of the beta subunit was determined from the sequences of tryptic, endoproteinase lysine-C, Staphylococcus aureus V8 protease, and cyanogen bromide peptides and in addition, a peptide derived from acid cleavage of an aspartyl-prolyl bond. The carboxyl-terminal sequence of the protein was determined by digestion with carboxypeptidase A. The alpha subunit contains 160 amino acids, one phycocyanobilin chromophore attached at residue 80 by a cysteinyl-thioether linkage, and the Mr calculated from the sequence is 18,160. The beta subunit contains 161 amino acids, one phycocyanobilin chromophore attached at residue 81 by a cysteinyl-thioether linkage, and the Mr calculated from the sequence is 18,125. The amino acid sequences of the alpha and beta subunits of allophycocyanin from C. caldarium are the first complete amino acid sequences of an allophycocyanin from a eukaryotic red alga. A matrix comparison of the alpha and beta subunits of C. caldarium allophycocyanin and phycocyanin (Offner, G.D., Brown-Mason, A.S., Ehrhardt, M. M., and Troxler, R. F. (1981) J. Biol. Chem. 256, 12167-12175; Troxler, R. F., Ehrhardt, M. M., Brown-Mason, A. S., and Offner, G. D. (1981) J. Biol. Chem. 256, 12176-12184) shows homology ranging from 26 to 39%. Comparison of the sequences of alpha and beta subunits of C. caldarium allophycocyanin with the sequences of the corresponding subunits of allophycocyanin from two prokaryotic cyanobacteria (Sidler, W., Gysi, J., Isker, E., and Zuber, H. (1981) Hoppe-Seyler's Z. Physiol. Chem. 362, 611-628; DeLange, R. J., Williams, L. C. and Glazer, A. N. (1981) J. Biol. Chem. 256, 9558-9566) shows homology ranging from 81 to 85%. The significance of this with respect to phycobiliprotein structure and function is discussed.
通过对单细胞红藻嗜热栖热菌中别藻蓝蛋白的α和β亚基进行自动Edman降解，并对化学和酶促裂解产生的蛋白质及肽段进行分析，确定了其完整氨基酸序列。α亚基的序列是通过胰蛋白酶、内肽酶赖氨酸-C、溴化氰肽段以及蛋白质的羧肽酶A和Y消化产物的序列确定的。β亚基的序列是通过胰蛋白酶、内肽酶赖氨酸-C、金黄色葡萄球菌V8蛋白酶、溴化氰肽段以及一个由天冬氨酰-脯氨酰键酸裂解产生的肽段的序列确定的。蛋白质的羧基末端序列通过羧肽酶A消化来确定。α亚基含有160个氨基酸，一个藻蓝胆素发色团通过半胱氨酰硫醚键连接在第80位残基上，根据序列计算的Mr为18,160。β亚基含有161个氨基酸，一个藻蓝胆素发色团通过半胱氨酰硫醚键连接在第81位残基上，根据序列计算的Mr为18,125。嗜热栖热菌别藻蓝蛋白α和β亚基的氨基酸序列是来自真核红藻的别藻蓝蛋白的首个完整氨基酸序列。对嗜热栖热菌别藻蓝蛋白的α和β亚基与藻蓝蛋白进行矩阵比较（Offner, G.D., Brown-Mason, A.S., Ehrhardt, M. M., and Troxler, R. F. (1981) J. Biol. Chem. 256, 12167 - 12175; Troxler, R. F., Ehrhardt, M. M., Brown-Mason, A. S., and Offner, G. D. (1981) J. Biol. Chem. 256, 12176 - 12184），显示同源性在26%至39%之间。将嗜热栖热菌别藻蓝蛋白的α和β亚基序列与来自两种原核蓝细菌的别藻蓝蛋白相应亚基序列进行比较（Sidler, W., Gysi, J., Isker, E., and Zuber, H. (1981) Hoppe-Seyler's Z. Physiol. Chem. 362, 611 - 628; DeLange, R. J., Williams, L. C. and Glazer, A. N. (1981) J. Biol. Chem. 256, 9558 - 9566），显示同源性在81%至85%之间。文中讨论了这对于藻胆蛋白结构和功能的意义。
