生物谷報(bào)道：美國(guó)亞利桑納州立大學(xué)（Arizona State University）的科學(xué)家 Neal Woodbury 及其研究團(tuán)隊(duì)提出光合作用反應(yīng)機(jī)制的新想法,，包含了在時(shí)間尺度為百萬(wàn)又百萬(wàn)分之一秒中所有蛋白質(zhì)的協(xié)同運(yùn)動(dòng)狀態(tài)之觀察。他們將所觀察到的現(xiàn)象以“Protein Dynamics Control the Kinetics of Initial Electron Transfer in Photosynthesis”為題發(fā)表于5月4日的著名期刊Science,。
植物或部分細(xì)菌可以利用光合作用,，透過(guò)捕捉光線能量中的光子，并吸取二氧化碳后轉(zhuǎn)化為氧氣及醣類,。這個(gè)維持地球上所有生命的生化過(guò)程,，仍有許多關(guān)鍵的疑問(wèn)未被解開(kāi)。研究人員利用Rhodobacter sphaeroides（紫色光合作用菌的一種）作為研究模式,，并將焦點(diǎn)集中在光合作用的反應(yīng)中心（reaction center）,，在此光線的能量能被導(dǎo)入一個(gè)特殊的葉綠素結(jié)合蛋白（chlorophyll binding proteins）上，由于其距離與方位已為最適化,，因此電子可以從其中一個(gè)葉綠素分子轉(zhuǎn)移到另一個(gè)身上,。當(dāng)葉綠素剛好位于對(duì)的位置，系統(tǒng)中蛋白質(zhì)的移動(dòng)就可被視為電子的副產(chǎn)物在葉綠素分子之間穿梭。
Woodbury 及其研究團(tuán)隊(duì)希望透過(guò)蛋白質(zhì)的突變,，觀察電子在分子及反應(yīng)中心轉(zhuǎn)移的情況,，另一位研究人員Wang 則利用一種超快速雷射系統(tǒng)來(lái)進(jìn)行研究，以高速圖像攝影機(jī)捕捉快如閃電的反應(yīng)數(shù)據(jù),，發(fā)現(xiàn)在光合作用產(chǎn)生時(shí),，反應(yīng)中心蛋白質(zhì)的移動(dòng)能使植物或細(xì)菌即使在環(huán)境條件都不理想的狀態(tài)下，仍能保有光線能量轉(zhuǎn)換的高效率狀態(tài),。
(資料來(lái)源 : Bio.com)
原始出處:
Science 4 May 2007:
Vol. 316. no. 5825, pp. 747 - 750
DOI: 10.1126/science.1140030
Reports
Protein Dynamics Control the Kinetics of Initial Electron Transfer in Photosynthesis
Haiyu Wang,1,2 Su Lin,1,2 James P. Allen,2 JoAnn C. Williams,2 Sean Blankert,1,2 Christa Laser,1,2 Neal W. Woodbury1,2*
Abstract
The initial electron transfer dynamics during photosynthesis have been studied in Rhodobacter sphaeroides reaction centers from wild type and 14 mutants in which the driving force and the kinetics of charge separation vary over a broad range. Surprisingly, the protein relaxation kinetics, as measured by tryptophan absorbance changes, are invariant in these mutants. By applying a reaction-diffusion model, we can fit the complex electron transfer kinetics of each mutant quantitatively, varying only the driving force. These results indicate that initial photosynthetic charge separation is limited by protein dynamics rather than by a static electron transfer barrier.
1 Biodesign Institute, Arizona State University, 1001 South McAllister Avenue, Tempe, AZ 85287–5201, USA.
2 Department of Chemistry and Biochemistry, Arizona State University, Tempe, AZ 85287–1604, USA.
* To whom correspondence should be addressed. E-mail: Nwoodbury@asu.edu
