Chlorophyll a/b binding-specificity in water-soluble chlorophyll protein
Chlorophyll a/b binding-specificity in water-soluble chlorophyll protein
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DOI：
10.1038/s41477-018-0273-z
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发表时间：
2018-11-01
期刊：
影响因子：
18
通讯作者：
Paulsen, Harald
中科院分区：
文献类型：
--
作者：
Palm, Daniel M.;Agostini, Alessandro;Paulsen, Harald
我们改变了叶绿素（Chl）结合位点的各种版本的水溶性叶绿素蛋白（WSCP）的氨基酸交换，以改变他们的喜好，无论是Chla或Chl B。WSCP非常适合这种突变分析，因为它形成了一个四聚体复合物，只有四个相同的Chl结合位点。4-6个氨基酸的环负责Chl a相对于Chl B的选择性。我们发现，在这个循环内的一个单一的氨基酸交换改变了相对叶绿素a/B的亲和力的一个因素为40。我们获得了结合Chl a或Chl B的WSCP变体的晶体结构。在这些结构中的叶绿素结合位点进行了比较，在植物的光合机构的主要捕光复合体（LHCII），以寻找类似的结构特征参与叶绿素a/B结合特异性。
We altered the chlorophyll (Chl) binding sites in various versions of water-soluble chlorophyll protein (WSCP) by amino acid exchanges to alter their preferences for either Chl a or Chl b. WSCP is ideally suited for this mutational analysis since it forms a tetrameric complex with only four identical Chl binding sites. A loop of 4-6 amino acids is responsible for Chl a versus Chl b selectivity. We show that a single amino acid exchange within this loop changes the relative Chl a/b affinities by a factor of 40. We obtained crystal structures of this WSCP variant binding either Chl a or Chl b. The Chl binding sites in these structures were compared with those in the major light-harvesting complex (LHCII) of the photosynthetic apparatus in plants to search for similar structural features involved in Chl a/b binding specificity.