雖然藻類(lèi)和植物需要大量光進(jìn)行光合作用,，但光照太多也會(huì)是有害的，造成嚴(yán)重氧化損傷,、甚至細(xì)胞死亡,。光合作用中光攝取的快速調(diào)控，通過(guò)“光合系統(tǒng)-II”中葉綠素分子由反饋調(diào)控的去激發(fā)為光合作用提供了一個(gè)安全閥,。但是，人們對(duì)真核藻類(lèi)中的這一防衛(wèi)體系的機(jī)制卻知之甚少,。
現(xiàn)在,，用缺少為L(zhǎng)HCSR編碼的三個(gè)基因中之兩個(gè)的單細(xì)胞藻類(lèi)“萊茵衣藻”的突變體所做的一項(xiàng)研究表明，這種蛋白（光攝取復(fù)合物超級(jí)家族中一個(gè)古老成員,，在維管植物中沒(méi)有）是在一個(gè)光照條件存在波動(dòng)的環(huán)境中生存所必需的,。這意味著，植物和藻類(lèi)利用不同蛋白來(lái)保護(hù)光合作用器官不受損傷,。（生物谷Bioon.com）
生物谷推薦原始出處：
Nature 462, 518-521 (26 November 2009) | doi:10.1038/nature08587
An ancient light-harvesting protein is critical for the regulation of algal photosynthesis
Graham Peers1,5, Thuy B. Truong1,2,6, Elisabeth Ostendorf3,6, Andreas Busch3, Dafna Elrad4, Arthur R. Grossman4, Michael Hippler3 & Krishna K. Niyogi1,2
1 Department of Plant and Microbial Biology, University of California, Berkeley, California 94720-3102, USA
2 Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
3 Institute of Plant Biochemistry and Biotechnology, University of Münster, 48143 Münster, Germany
4 Department of Plant Biology, Carnegie Institution, Stanford, California 94305, USA
5 Present address: Synthetic Genomics, Inc., 11149 North Torrey Pines Road, Suite 100, La Jolla, California 92037, USA.
6 These authors contributed equally to this work.
Correspondence to: Michael Hippler3Krishna K. Niyogi1,2 Correspondence and requests for materials should be addressed to K.K.N.or M.H.
Light is necessary for photosynthesis, but its absorption by pigment molecules such as chlorophyll can cause severe oxidative damage and result in cell death. The excess absorption of light energy by photosynthetic pigments has led to the evolution of protective mechanisms that operate on the timescale of seconds to minutes and involve feedback-regulated de-excitation of chlorophyll molecules in photosystem II (qE). Despite the significant contribution of eukaryotic algae to global primary production1, little is known about their qE mechanism, in contrast to that in flowering plants2, 3. Here we show that a qE-deficient mutant of the unicellular green alga Chlamydomonas reinhardtii, npq4, lacks two of the three genes encoding LHCSR (formerly called LI818). This protein is an ancient member of the light-harvesting complex superfamily, and orthologues are found throughout photosynthetic eukaryote taxa4, except in red algae and vascular plants. The qE capacity of Chlamydomonas is dependent on environmental conditions and is inducible by growth under high light conditions. We show that the fitness of the npq4 mutant in a shifting light environment is reduced compared to wild-type cells, demonstrating that LHCSR is required for survival in a dynamic light environment. Thus, these data indicate that plants and algae use different proteins to dissipate harmful excess light energy and protect the photosynthetic apparatus from damage.
