Hess W R, Partensky F, van der Staay G W, Garcia-Fernandez J M, Börner T, Vaulot D
Department of Biology, Humboldt-University, Berlin, Germany. Wolfgang=
Proc Natl Acad Sci U S A. 1996 Oct 1;93(20):11126-30. doi: 10.1073/pnas.93.20.11126.
Prochlorococcus marinus CCMP 1375, a ubiquitous and ecologically important marine prochlorophyte, was bound to possess functional genes coding for the alpha and beta subunits of a phycobiliprotein. The latter is similar to phycoerythrins (PE) from marine Synechococcus cyanobacteria and bind a phycourobilin-like pigment as the major chromophore. However, differences in the sequences of the alpha and beta chains compared with known PE subunits and the presence of a single bilin attachment site on the alpha subunit designate it as a novel PE type, which we propose naming PE-III. P. marinus is the sole prokaryotic organisms known so far that contains chlorophylls a and b as well as phycobilins. These data strongly suggest that the common ancestor of prochlorophytes and the Synechococcus cyanobacteria contained phycobilins. Flow cytometric data from the tropical Pacific Ocean provide evidence that deep populations of Prochlorococcus possess low amounts of a PE-like pigment, which could serve either in light harvesting or nitrogen storage or both.
海洋原绿球藻CCMP 1375是一种广泛分布且在生态上具有重要意义的海洋原绿藻，必然拥有编码藻胆蛋白α和β亚基的功能基因。后者类似于海洋聚球蓝细菌中的藻红蛋白（PE），并结合一种类藻尿胆素色素作为主要发色团。然而，与已知的PE亚基相比，α和β链的序列存在差异，并且α亚基上存在单个胆色素附着位点，这表明它是一种新型的PE类型，我们建议将其命名为PE-III。海洋原绿球藻是迄今为止已知的唯一同时含有叶绿素a和b以及藻胆素的原核生物。这些数据有力地表明，原绿藻和聚球蓝细菌的共同祖先含有藻胆素。来自热带太平洋的流式细胞术数据提供了证据，表明海洋原绿球藻的深层群体含有少量类似PE的色素，其可能用于光捕获或氮储存或两者兼而有之。
