Riethman H C, Mawhinney T P, Sherman L A
Division of Biological Sciences, University of Missouri-Columbia 65211.
J Bacteriol. 1988 Jun;170(6):2433-40. doi: 10.1128/jb.170.6.2433-2440.1988.
Concanavalin A-reactive linker and anchor subunits of phycobilisomes from Anacystis nidulans R2 (H. C. Riethman, T. P. Mawhinney, and L. A. Sherman, FEBS Lett. 215:209-214, 1987) were purified electrophoretically and analyzed for carbohydrate composition and quantity. Different quantities of glucose and N-acetylgalactosamine were found on the concanavalin A-reactive subunits analyzed. Proteolytic analysis of the purified subunits suggested that small regions of the 33- and 27-kilodalton linker polypeptides previously shown to be important for in vitro phycobilisome assembly contained the concanavalin A-reactive carbohydrates present on these subunits. The linker and anchor subunits from the morphologically different phycobilisome of Synechocystis sp. strain PCC6714 were also shown to be concanavalin A reactive. Membranes from iron-starved Anacystis nidulans, which lack assembled phycobilisomes and are associated with glycogen deposits, were shown to be depleted of linker and anchor proteins and to accumulate very large quantities of a concanavalin A-reactive, extrinsic membrane glycoprotein. We suggest that this iron stress-induced glycoprotein is associated with the glycogen deposits on the thylakoid surface and that the glycosylation of phycobilisome linker and anchor subunits is involved in the physiological regulation of phycobilisome assembly and degradation.
来自集胞藻6803 R2（H.C.里特曼、T.P.莫温尼和L.A.谢尔曼，《欧洲生物化学学会联合会快报》215:209 - 214，1987）的藻胆体的伴刀豆球蛋白A反应性连接子和锚定亚基通过电泳进行了纯化，并对其碳水化合物组成和含量进行了分析。在所分析的伴刀豆球蛋白A反应性亚基上发现了不同量的葡萄糖和N - 乙酰半乳糖胺。对纯化亚基的蛋白水解分析表明，先前显示对体外藻胆体组装很重要的33千道尔顿和27千道尔顿连接多肽的小区域含有这些亚基上存在的伴刀豆球蛋白A反应性碳水化合物。来自集胞藻属PCC6714形态不同的藻胆体的连接子和锚定亚基也显示出对伴刀豆球蛋白A有反应性。来自缺铁的集胞藻6803的膜，其缺乏组装好的藻胆体且与糖原沉积物相关，显示出连接子和锚定蛋白减少，并积累了大量的伴刀豆球蛋白A反应性外在膜糖蛋白。我们认为这种铁应激诱导的糖蛋白与类囊体表面的糖原沉积物相关，并且藻胆体连接子和锚定亚基的糖基化参与了藻胆体组装和降解的生理调节。
