Wilbanks S M, de Lorimier R, Glazer A N
Division of Biochemistry and Molecular Biology, University of California, Berkeley 94720.
J Biol Chem. 1991 May 25;266(15):9535-9.
The genes for the alpha and beta subunits of a novel six bilin-bearing (class II) phycoerythrin were cloned from Synechococcus sp. WH8020 and sequenced. The cloned genes (mpeA and mpeB) were detected by homology with the genes for C-phycoerythrin from Pseudanabaena sp. PCC7409. The mpe locus occurs once in the genome and is arranged similarly to that of many other phycobiliproteins, with mpeA shortly 3' of mpeB. Sequence comparison suggests that this phycoerythrin (and perhaps all class II phycoerythrins) occupy a branch of the phycoerythrin family separate from five-chromophore per alpha beta (class I) phycoerythrins, C-phycoerythrin, and B-phycoerythrin. The position of the sixth chromophore of the class II phycoerythrin of WH8020 was determined by comparison of the amino acid sequence of the chromopeptides (Ong, L. J., and Glazer, A. N. (1991) J. Biol Chem. 266, 9515-9527) with the sequence deduced from the gene. This located the chromophore at residue 75 of the alpha subunit, very close to the alpha-83 chromophore in the primary structure and, presumably, in the three-dimensional structure.
从聚球藻属（Synechococcus）sp. WH8020中克隆并测序了一种新型的含六个藻胆素（II类）藻红蛋白的α和β亚基的基因。通过与假鱼腥藻属（Pseudanabaena）sp. PCC7409的C-藻红蛋白基因的同源性检测克隆的基因（mpeA和mpeB）。mpe基因座在基因组中只出现一次，其排列方式与许多其他藻胆蛋白类似，mpeA在mpeB的3'端附近。序列比较表明，这种藻红蛋白（可能所有II类藻红蛋白）在藻红蛋白家族中占据一个分支，与每个αβ含五个发色团（I类）藻红蛋白、C-藻红蛋白和B-藻红蛋白分开。通过将发色肽的氨基酸序列（Ong, L. J., and Glazer, A. N. (1991) J. Biol Chem. 266, 9515 - 9527）与从基因推导的序列进行比较，确定了WH8020的II类藻红蛋白第六个发色团的位置。这将发色团定位在α亚基的第75位残基处，在一级结构中非常接近α-83发色团，并且大概在三维结构中也是如此。
