Mulo Paula
Molecular Plant Biology, Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland.
Biochim Biophys Acta. 2011 Aug;1807(8):927-34. doi: 10.1016/j.bbabio.2010.10.001. Epub 2010 Oct 8.
Ferredoxin-NADP(+) oxidoreductase (FNR) is a ubiquitous flavin adenine dinucleotide (FAD)-binding enzyme encoded by a small nuclear gene family in higher plants. The chloroplast targeted FNR isoforms are known to be responsible for the final step of linear electron flow transferring electrons from ferredoxin to NADP(+), while the putative role of FNR in cyclic electron transfer has been under discussion for decades. FNR has been found from three distinct chloroplast compartments (i) at the thylakoid membrane, (ii) in the soluble stroma, and (iii) at chloroplast inner envelope. Recent in vivo studies have indicated that besides the membrane-bound FNR, also the soluble FNR is photosynthetically active. Two chloroplast proteins, Tic62 and TROL, were recently identified and shown to form high molecular weight protein complexes with FNR at the thylakoid membrane, and thus seem to act as the long-sought molecular anchors of FNR to the thylakoid membrane. Tic62-FNR complexes are not directly involved in photosynthetic reactions, but Tic62 protects FNR from inactivation during the dark periods. TROL-FNR complexes, however, have an impact on the photosynthetic performance of the plants. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts.
铁氧化还原蛋白-NADP(+)氧化还原酶（FNR）是一种普遍存在的黄素腺嘌呤二核苷酸（FAD）结合酶，由高等植物中的一个小核基因家族编码。已知靶向叶绿体的FNR同工型负责线性电子流的最后一步，即将电子从铁氧化还原蛋白转移到NADP(+)，而FNR在循环电子传递中的假定作用已经讨论了几十年。FNR已在叶绿体的三个不同区室中被发现：（i）类囊体膜上，（ii）可溶性基质中，以及（iii）叶绿体内膜上。最近的体内研究表明，除了膜结合FNR外，可溶性FNR也具有光合活性。最近鉴定出两种叶绿体蛋白Tic62和TROL，并表明它们在类囊体膜上与FNR形成高分子量蛋白复合物，因此似乎充当了长期寻找的FNR与类囊体膜的分子锚。Tic62-FNR复合物不直接参与光合反应，但Tic62可保护FNR在黑暗时期不被灭活。然而，TROL-FNR复合物对植物的光合性能有影响。本文是名为“叶绿体中电子传递的调控”的特刊的一部分。
