Tsiavos Theodoros, Ioannidis Nikolaos E, Kotzabasis Kiriakos
Department of Biology, University of Crete, P.O. Box 2208, GR-71409 Heraklion, Crete, Greece.
Biochim Biophys Acta. 2012 May;1817(5):735-43. doi: 10.1016/j.bbabio.2012.01.007. Epub 2012 Jan 21.
Dissipation of excess excitation energy within the light-harvesting complex of Photosystem II (LHC II) is a main process in plants, which is measured as the non-photochemical quenching of chlorophyll fluorescence or qE. We showed in previous works that polyamines stimulate qE in higher plants in vivo and in eukaryotic algae in vitro. In the present contribution we have tested whether polyamines can stimulate quenching in trimeric LHC II and monomeric light-harvesting complex b proteins from higher plants. The tetramine spermine was the most potent quencher and induced aggregation of LHC II trimers, due to its highly cationic character. Two transients are evident at 100 μM and 350 μM for the fluorescence and absorbance signals of LHC II respectively. On the basis of observations within this work, some links between polyamines and the activation of qE in vivo is discussed.
在光系统II（LHC II）的捕光复合物中耗散过量的激发能是植物中的一个主要过程，该过程通过叶绿素荧光的非光化学猝灭或qE来衡量。我们在之前的研究中表明，多胺在体内能刺激高等植物的qE，在体外能刺激真核藻类的qE。在本论文中，我们测试了多胺是否能刺激高等植物三聚体LHC II和单体捕光复合物b蛋白的猝灭。四胺精胺是最有效的猝灭剂，由于其高度阳离子特性，它会诱导LHC II三聚体聚集。对于LHC II的荧光和吸光度信号，在100μM和350μM时分别有两个明显的瞬态。基于本研究中的观察结果，讨论了多胺与体内qE激活之间的一些联系。
