Lundell D J, Glazer A N
J Biol Chem. 1983 Jan 25;258(2):894-901.
The 18 S subassembly particles obtained by partial dissociation of phycobilisomes from Synechococcus 6301 (Anacystis nidulans) strain AN 112 contain approximately one-half of the mass of the phycobilisome and include core-rod junctions (Yamanaka, G., Lundell, D. J., and Glazer, A. N. (1982) J. Biol. Chem. 257, 4077-4086). The polypeptide composition of 18 S complexes, determined by analysis of uniformly 14C-labeled phycobilisomes, gave the following stoichiometry: 75K:27K:18.3K:alpha beta allophycocyanin monomer: alpha beta phycocyanin monomer of 1:2:1:5:6; where 75K, 27K, etc. represent polypeptides of 75, 27 kilodaltons, etc. The 18.3K polypeptide is a hitherto underscribed biliprotein bearing a single phycocyanobilin. The NH2-terminal sequence of this subunit was determined to be homologous to that of the beta subunit of allophycocyanin. Chromatography of products resulting from limited trypsin treatment of the 18 S complex led to the isolation of three subcomplexes: a mixture of (alpha beta)3 . 22K and (alpha beta)3 . 24K phycocyanin complexes, an (alpha beta)3 allophycocyanin trimer, and an (alpha beta)2 . 18.3K.40K.11K allophycocyanin-containing complex. The 22K and 24K components were products of the degradation of the 27K polypeptides, whereas the 40K and 11K components were derived from the 75K polypeptide. The subcomplexes accounted for the composition of the 18 S complex. Determination of the composition, stoichiometry, and spectroscopic properties of the subcomplexes has led to a model of the polypeptide arrangement within the 18 S complex and of the pathway of energy transfer among these polypeptides.
通过对集胞藻6301（集球藻）菌株AN 112的藻胆体进行部分解离获得的18 S亚组装颗粒含有藻胆体质量的大约一半，并且包括核心 - 棒状连接点（山中，G.，伦德尔，D. J.，和格拉泽，A. N.（1982年）《生物化学杂志》257，4077 - 4086）。通过对均匀14C标记的藻胆体进行分析确定的18 S复合物的多肽组成给出了以下化学计量比：75K:27K:18.3K:αβ别藻蓝蛋白单体:αβ藻蓝蛋白单体为1:2:1:5:6；其中75K、27K等代表75、27千道尔顿等的多肽。18.3K多肽是一种迄今未充分描述的带有单个藻蓝胆素的双蛋白。该亚基的NH2末端序列被确定与别藻蓝蛋白的β亚基同源。对18 S复合物进行有限胰蛋白酶处理产生的产物进行色谱分析，导致分离出三个亚复合物：(αβ)3·22K和(αβ)3·24K藻蓝蛋白复合物的混合物、一个(αβ)3别藻蓝蛋白三聚体以及一个(αβ)2·18.3K·40K·11K含别藻蓝蛋白的复合物。22K和24K组分是27K多肽降解的产物，而40K和11K组分源自75K多肽。这些亚复合物解释了18 S复合物的组成。对亚复合物的组成、化学计量比和光谱性质的测定导致了18 S复合物内多肽排列以及这些多肽之间能量转移途径的模型。
