Abstract：
Cyanobacteria, red algae, and cryptophytes produce two classes of proteins for light-harvesting: water-soluble phycobiliproteins and membrane-intrinsic proteins that bind chlorophylls and carotenoids. In cyanobacteria, red algae, and glaucophytes, phycobilisomes (PBS) are complexes of brightly colored phycobiliproteins and linker (assembly) proteins. To date, six structural classes of phycobilisomes have been described: hemiellipsoidal, block-shaped, hemidiscoidal, bundle-shaped, paddle-shaped, and far-red-light bicylindrical. Two additional antenna complexes containing single types of phycobiliproteins have also been described. Since 2017, structures have been reported for examples of all of these complexes except bundle-shaped phycobilisomes by cryogenic electron microscopy. Phycobilisomes range in size from about 4.6 to 18 MDa and can include ∼900 polypeptides and bind >2000 chromophores. Cyanobacteria additionally produce membrane-associated proteins of the PsbC/CP43 superfamily of Chl a/b/d-binding proteins, including the iron-stress protein IsiA and other paralogous chlorophyll-binding proteins that can form antenna complexes with Photosystem I and/or Photosystem II. Red and cryptophyte algae also produce chlorophyll-binding proteins associated with Photosystem I but which belong to the chlorophyll a/b-binding (CAB) protein superfamily and which are unrelated to the chlorophyll-binding proteins (CBP) of cyanobacteria. This review describes recent progress in structure determination for phycobilisomes and the chlorophyll proteins of cyanobacteria, red algae, and cryptophytan algae.
摘要：
蓝细菌,红藻,隐藻产生两类用于捕光的蛋白质：水溶性藻胆蛋白和结合叶绿素和类胡萝卜素的膜内在蛋白。在蓝细菌中，红藻,和芒草，藻胆体（PBS）是色彩鲜艳的藻胆蛋白和接头（组装）蛋白的复合物。迄今为止,已经描述了六个结构类别的藻胆体：半椭圆形，块状,半盘状,束状,桨状,和远红光的双圆柱。还描述了含有单一类型的藻胆蛋白的两个另外的触角复合物。自2017年以来，通过低温电子显微镜已经报道了所有这些复合物的结构，除了束状藻胆小体。藻胆体的大小范围约为4.6至18MDa，可包括约900个多肽，并结合>2000个发色团。蓝细菌还产生Chla/b/d结合蛋白的PsbC/CP43超家族的膜相关蛋白，包括铁应激蛋白IsiA和其他可以与光系统I和/或光系统II形成天线复合物的旁系叶绿素结合蛋白。红色和隐藻藻类还产生与光系统I相关的叶绿素结合蛋白，但属于叶绿素a/b结合（CAB）蛋白超家族，与蓝细菌的叶绿素结合蛋白（CBP）无关。本文综述了蓝细菌藻胆体和叶绿素蛋白结构测定的最新进展。红藻,和隐藻。
