The PHOTOSYNTHESIS AFFECTED MUTANT68-LIKE Protein Evolved from a PSII Assembly Factor to Mediate Assembly of the Chloroplast NAD(P)H Dehydrogenase Complex in Arabidopsis
The PHOTOSYNTHESIS AFFECTED MUTANT68-LIKE Protein Evolved from a PSII Assembly Factor to Mediate Assembly of the Chloroplast NAD(P)H Dehydrogenase Complex in Arabidopsis
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DOI：
10.1105/tpc.113.114785
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发表时间：
2013-10-01
期刊：
影响因子：
11.6
通讯作者：
Leister, Dario
中科院分区：
文献类型：
--
作者：
Armbruster, Ute;Ruehle, Thilo;Leister, Dario
在维管植物中，叶绿体NAD(P)H脱氢酶复合体(NDH-C)由五个不同的亚复合体组成，即膜跨膜(SubM)和腔(Sub1)亚复合体，以及Suba、Subb和Sube。人们对组装过程本身知之甚少。维管植物基因组编码两个相关的内源类囊体蛋白，光合作用影响的MUTANT68(PAM68)，光系统II组装因子，以及光合作用影响的MUTANT68-like(PAM68L)。如我们在这里所示，在pam68l-1突变体中，拟南芥PAM68L的失活证明PAM68L是一个NDH-C组装因子。该突变体缺乏功能性NDH全复合体，并积累三种不同的NDH-C组装中间体(SubB、SubM和SuBA+L)，这三种中间体也存在于SubB组装缺陷(NDF5)或SubM表达缺陷突变(ChloroResspiratory ReDUCTION4-3突变体)中。蓝藻聚球藻PCC6803和苔藓Physcomitrella patens中的NDH-C组装不需要PAM68蛋白，这一点通过对这些物种中单拷贝PAM68基因的敲除线分析证明。我们得出结论，PAM68L介导了含有SubB和SubM的中间体与含有SuBA和Sub1的复合体的附着。SubL和PAM68L在从像P.patens这样的苔藓到开花植物的过渡过程中的进化出现表明，NDH-C复杂性的增加可能是由于PAM68L等进化上新的组装因子的招募所致。
In vascular plants, the chloroplast NAD(P)H dehydrogenase complex (NDH-C) is assembled from five distinct subcomplexes, the membrane-spanning (subM) and the luminal (subL) subcomplexes, as well as subA, subB, and subE. The assembly process itself is poorly understood. Vascular plant genomes code for two related intrinsic thylakoid proteins, PHOTOSYNTHESIS-AFFECTED MUTANT68 (PAM68), a photosystem II assembly factor, and PHOTOSYNTHESIS-AFFECTED MUTANT68-LIKE (PAM68L). As we show here, inactivation of Arabidopsis thaliana PAM68L in the pam68l-1 mutant identifies PAM68L as an NDH-C assembly factor. The mutant lacks functional NDH holocomplexes and accumulates three distinct NDH-C assembly intermediates (subB, subM, and subA+L), which are also found in mutants defective in subB assembly (ndf5) or subM expression (CHLORORESPIRATORY REDUCTION4-3 mutant). NDH-C assembly in the cyanobacterium Synechocystis sp PCC 6803 and the moss Physcomitrella patens does not require PAM68 proteins, as demonstrated by the analysis of knockout lines for the single-copy PAM68 genes in these species. We conclude that PAM68L mediates the attachment of subB- and subM-containing intermediates to a complex that contains subA and subL. The evolutionary appearance of subL and PAM68L during the transition from mosses like P. patens to flowering plants suggests that the associated increase in the complexity of the NDH-C might have been facilitated by the recruitment of evolutionarily novel assembly factors like PAM68L.