Environment and Biotechnology Centre, Faculty of Life and Social Sciences, Swinburne University of Technology, PO Box 218, Hawthorn, VIC 3122, Australia.
Physiol Plant. 2011 Dec;143(4):385-95. doi: 10.1111/j.1399-3054.2011.01503.x. Epub 2011 Sep 14.
FK506-binding proteins (FKBPs) and cyclophilins, collectively called immunophilins, conserve peptidyl-prolyl cis/trans isomerase (PPIase) active sites, although many lack PPIase activity. The chloroplast thylakoid contains a large proportion of the plant immunophilin family, but their functions within this compartment are unclear. Some lumenal immunophilins are important for assembly of photosynthetic complexes, implicating them in the maintenance and turnover of the photosynthetic apparatus during acclimation processes. In this investigation into the functions of three FKBPs localized to the thylakoid of Triticum aestivum (wheat), we present the first evidence of PPIase activity in the thylakoid of a cereal plant, and also show that PPIase activity is not conserved in all lumenal FKBPs. Using yeast two-hybrid analysis we found that the PPIase-active FKBP13 interacts with the globular domain of the wheat Rieske protein, with potential impact on photosynthetic electron transfer. Specific interaction partners for PPIase-deficient FKBP16-1 and FKBP16-3 link these isoforms to photosystem assembly.
FK506 结合蛋白（FKBP）和亲环素，统称为免疫亲和素，它们都具有肽基脯氨酰顺反异构酶（PPIase）活性位点，尽管许多 FKBP 缺乏 PPIase 活性。质体类囊体含有大量植物免疫亲和素家族，但它们在这个隔室中的功能尚不清楚。一些腔室免疫亲和素对于光合复合物的组装很重要，这表明它们在适应过程中参与了光合器官的维持和周转。在对定位于小麦（Triticum aestivum）类囊体的三种 FKBP 的功能进行的研究中，我们首次提供了在谷物植物类囊体中存在 PPIase 活性的证据，同时还表明并非所有腔室 FKBP 都具有 PPIase 活性。通过酵母双杂交分析，我们发现 PPIase 活性的 FKBP13 与小麦 Rieske 蛋白的球形结构域相互作用，这可能对光合作用电子传递有影响。对于 PPIase 缺失的 FKBP16-1 和 FKBP16-3，其特异性相互作用伙伴与光系统组装有关。
