Raczyńska Katarzyna Dorota, Augustyniak Halina
Department of Plant Molecular Biology, Institute of Molecular Biology and Biotechnology, Adam Mickiewicz University, 60-371 Poznań, Poland.
Postepy Biochem. 2005;51(4):440-6.
PPR proteins belong to large family of nucleic acid binding proteins, mainly RNA-binding proteins. Their name is defined by the presence of so-called pentatricopeptide repeat (PPR), a degenerate 35-aminoacid repeats containing from 2 up to 26 such motifs arrayed in tandem of at least in one pair. PPR motif consists of two a helices A and B forming a superhelix enclosing a groove or tunnel which is likely to be the ligand-binding site. PPR proteins are targeted mainly to mitochondria and chloroplasts where they are mainly involved in posttranscriptional processes and translation. Among PPR proteins they were also found restorer gene products which restorer pollen fertility. Some PPR proteins play roles as adaptors and partner in protein-protein interaction. PPR protein genes were discovered in all analyzed eukariotic genomes. They are especially abundant in plants.
PPR蛋白属于核酸结合蛋白的大家族，主要是RNA结合蛋白。它们的名字由所谓的五肽重复序列（PPR）的存在来定义，这是一种由2至26个这样的基序串联排列而成的35个氨基酸的简并重复序列，至少有一对。PPR基序由两个α螺旋A和B组成，形成一个包围可能是配体结合位点的凹槽或通道的超螺旋。PPR蛋白主要定位于线粒体和叶绿体，它们主要参与转录后过程和翻译。在PPR蛋白中还发现了恢复花粉育性的恢复基因产物。一些PPR蛋白在蛋白质-蛋白质相互作用中作为衔接子和伙伴发挥作用。在所有分析过的真核生物基因组中都发现了PPR蛋白基因。它们在植物中尤其丰富。
