Pérez-Bueno Maria L, Johnson Matthew P, Zia Ahmad, Ruban Alexander V, Horton Peter
Department of Molecular Biology and Biotechnology, University of Sheffield, Firth Court, Western Bank, Sheffield S10 2TN, United Kingdom.
FEBS Lett. 2008 Apr 30;582(10):1477-82. doi: 10.1016/j.febslet.2008.03.040. Epub 2008 Apr 7.
Nonphotochemical quenching (NPQ) is the photoprotective dissipation of energy in photosynthetic membranes. The hypothesis that the DeltapH-dependent component of NPQ (qE) component of non-photochemical quenching is controlled allosterically by the xanthophyll cycle has been tested using Arabidopsis mutants with different xanthophyll content and composition of Lhcb proteins. The titration curves of qE against DeltapH were different in chloroplasts containing zeaxanthin or violaxanthin, proving their roles as allosteric activator and inhibitor, respectively. The curves differed in mutants deficient in lutein and specific Lhcb proteins. The results show that qE is determined by xanthophyll occupancy and the structural interactions within the antenna that govern allostericity.
非光化学猝灭（NPQ）是光合膜中能量的光保护耗散。非光化学猝灭的依赖ΔpH的组分（qE）由叶黄素循环别构调控这一假说，已通过使用具有不同叶黄素含量和Lhcb蛋白组成的拟南芥突变体进行了验证。在含有玉米黄质或紫黄质的叶绿体中，qE相对于ΔpH的滴定曲线不同，分别证明了它们作为别构激活剂和抑制剂的作用。在缺乏叶黄素和特定Lhcb蛋白的突变体中，曲线也有所不同。结果表明，qE由叶黄素占据情况以及天线内控制别构性的结构相互作用决定。
