Troxler R F, Greenwald L S, Zilinskas B A
J Biol Chem. 1980 Oct 10;255(19):9380-7.
Allophycocyanin from Nostoc sp. phycobilisomes was separated into four spectrally distinct components designated allophycocyanin I, B, II, and III by adsorption chromatography on brushite columns. Allophycocyanins I and B had red-shifted fluorescence emission maxima, and on this basis, may function in transfer of excitation energy from phycobilisomes to chlorophyll a. Allophycyanins II and III, which together comprise 70% of the total allophycocyanin, have absorption maxima at 648 nm and 650 nm, respectively, and probably transfer excitation energy from phycocyanin to allophycocyanins I and B, in addition to serving a structural function. Allophycocyanin I was resolved into alpha, beta, and gamma subunits with apparent molecular weights of 18,000, 17,000, and 35,000, respectively, whereas allophycocyanin B was resolved into two subunits with apparent molecular weights of 16,100 and 15,300, using a modified Weber and Osborn gel electrophoresis system (Brown, A. S., and Troxler, R. F. (1977) Biochem. J. 163, 571-581). In the same gel system, allophycocyanins II and III were each resolved into alpha and beta subunits with apparent molecular weights of 18,000 and 17,000, respectively. The subunits of allophycocyanins I, II, and III were isolated by gel filtration and ion exchange chromatography and the amino acid compositions determined. Automated sequence analysis demonstrated that the first 30 amino acids at the NH2 terminus of alpha subunits, and the beta subunits, of allophycocyanins I to III were identical. alpha Subunits: Ser-Ile-Val-Thr-Lys-Ser-Ile-Val-Asn-Ala-Asp-Ala-Glu-Ala-Arg-Tyr-Leu-Ser-Pro-Gly -Glu-Leu-Asp-Arg-Ile-Lys-Ser-Phe-Val-Thr- beta Subunits: Ala-Gln-Asp-Ala-Ile-Thr-Ala-Val-Ile-Asn-Ala-Ala-Asp-Val-Gln-Gly-Lys-Tyr-Leu-Asp-Ala-Thr-Ala-Leu-Ser-Lys-Leu-Lys-Ala-Tyr- The gamma subunit of allophycocyanin I and both subunits of allophycocyanin B appeared to be blocked at the NH2 terminus, suggesting that the allophycocyanin B subunits may be different gene products than those of allophycocyanins I to III, or if the same, the subunits of allophycocyanin B undergo proteolytic modification after initial synthesis.
通过在透钙磷石柱上进行吸附色谱，将来自念珠藻属藻胆体的别藻蓝蛋白分离成四个光谱特性不同的组分，分别命名为别藻蓝蛋白I、B、II和III。别藻蓝蛋白I和B具有红移的荧光发射最大值，基于此，它们可能在将激发能从藻胆体传递到叶绿素a中发挥作用。别藻蓝蛋白II和III一起占总别藻蓝蛋白的70%，它们的吸收最大值分别在648nm和650nm，除了具有结构功能外，可能还将激发能从藻蓝蛋白传递到别藻蓝蛋白I和B。使用改良的韦伯和奥斯本凝胶电泳系统（布朗，A.S.，和特罗克斯勒，R.F.（1977年）《生物化学杂志》163，571 - 581），别藻蓝蛋白I被解析为α、β和γ亚基，其表观分子量分别为18,000、17,000和35,000，而别藻蓝蛋白B被解析为两个亚基，表观分子量分别为16,100和15,300。在同一凝胶系统中，别藻蓝蛋白II和III各自被解析为α和β亚基，表观分子量分别为18,000和17,000。通过凝胶过滤和离子交换色谱分离出别藻蓝蛋白I、II和III的亚基，并测定了氨基酸组成。自动序列分析表明，别藻蓝蛋白I至III的α亚基和β亚基在NH2末端的前30个氨基酸是相同的。
α亚基：Ser - Ile - Val - Thr - Lys - Ser - Ile - Val - Asn - Ala - Asp - Ala - Glu - Ala - Arg - Tyr - Leu - Ser - Pro - Gly - Glu - Leu - Asp - Arg - Ile - Lys - Ser - Phe - Val - Thr -
β亚基：Ala - Gln - Asp - Ala - Ile - Thr - Ala - Val - Ile - Asn - Ala - Ala - Asp - Val - Gln - Gly - Lys - Tyr - Leu - Asp - Ala - Thr - Ala - Leu - Ser - Lys - Leu - Lys - Ala - Tyr -
别藻蓝蛋白I的γ亚基和别藻蓝蛋白B的两个亚基在NH2末端似乎被封闭，这表明别藻蓝蛋白B亚基可能是与别藻蓝蛋白I至III不同的基因产物，或者如果是相同的，别藻蓝蛋白B亚基在初始合成后会经历蛋白水解修饰。
