據(jù)美國物理學(xué)家組織網(wǎng)近日報(bào)道，美國卡內(nèi)基學(xué)院,、加利福尼亞大學(xué)洛杉磯分校與美國能源部聯(lián)合研究院利用先進(jìn)的計(jì)算機(jī)工具,，分析了28種植物中與光合作用相關(guān)的基因組，編制出與光合作用有關(guān)的597個編碼基因蛋白的詳細(xì)目錄,，從而可更好地從基因?qū)W角度研究支撐植物生理與生態(tài)的各種生物過程,。研究論文發(fā)表在最新一期《生物化學(xué)雜志》上。
這597個來自植物和綠藻基因組的編碼蛋白,，稱為GreenCut蛋白質(zhì),，是光合生物特有的蛋白。其中286個是當(dāng)前已知的功能蛋白,，剩下的311個尚無法與特定的生物過程聯(lián)系起來,。
葉綠體是進(jìn)行光合作用的工作間，有52%的GreenCut蛋白質(zhì)位于葉綠體上,。目前人們普遍認(rèn)為,，葉綠體是從一種能進(jìn)行光合作用的單細(xì)胞細(xì)菌——藻青菌進(jìn)化而來。大約15億年前,，藻青菌被更加復(fù)雜的,、不能進(jìn)行光合作用的細(xì)胞所吞噬，兩種生物之間形成了最早的共生關(guān)系,。在進(jìn)化過程中,，藻青菌將它的大部分基因信息轉(zhuǎn)移給了宿主生物的細(xì)胞核,，喪失了獨(dú)立生存能力。
“這種基因減退的藻青菌是葉綠體的基礎(chǔ),，卻保持了它的光合作用能力和某些基本的代謝功能,，如合成氨基酸和脂肪。葉綠體中發(fā)生的這些過程,，也必須和其他代謝過程緊密結(jié)合在一起,。”卡內(nèi)基學(xué)院研究員格魯斯曼解釋說。
最近發(fā)現(xiàn)的證據(jù)表明,，并非所有的GreenCut蛋白質(zhì)都在葉綠體上,，許多參與光合作用的GreenCut蛋白對于植物其他功能作用也起著關(guān)鍵作用，可能涉及新陳代謝調(diào)控,、DNA轉(zhuǎn)錄控制,、線粒體產(chǎn)生能量、過氧物酶體（能凈化室內(nèi)空氣）等細(xì)胞器正常功能的發(fā)揮,。
進(jìn)一步擴(kuò)展研究范圍之后,，研究人員還發(fā)現(xiàn)，在古老的藻青菌,、紅藻及硅藻等其他單細(xì)胞藻類中,，也保留了多種GreenCut蛋白質(zhì)。格魯斯曼表示,，比較多種生物中所含有的GreenCut蛋白質(zhì),，有助于進(jìn)一步揭開這些蛋白質(zhì)在光合細(xì)胞中的作用，研究葉綠體的進(jìn)化過程,，以及在不同條件下,，光合細(xì)胞是如何調(diào)整變化以適應(yīng)生存環(huán)境的。（生物谷Bioon.com）
生物谷推薦原文出處：
The Journal of Biological Chemistry DOI:10.1074/jbc.M111.233734
The GreenCut2 Resource, a Phylogenomically Derived Inventory of Proteins Specific to the Plant Lineage
Steven J. Karpowicz, Simon E. Prochnik, Arthur R. Grossman and Sabeeha S. Merchant
The plastid is a defining structure of photosynthetic eukaryotes and houses many plant-specific processes, including the light reactions, carbon fixation, pigment synthesis, and other primary metabolic processes. Identifying proteins associated with catalytic, structural, and regulatory functions that are unique to plastid-containing organisms is necessary to fully define the scope of plant biochemistry. Here, we performed phylogenomics on 20 genomes to compile a new inventory of 597 nucleus-encoded proteins conserved in plants and green algae but not in non-photosynthetic organisms. 286 of these proteins are of known function, whereas 311 are not characterized. This inventory was validated as applicable and relevant to diverse photosynthetic eukaryotes using an additional eight genomes from distantly related plants (including Micromonas, Selaginella, and soybean). Manual curation of the known proteins in the inventory established its importance to plastid biochemistry. To predict functions for the 52% of proteins of unknown function, we used sequence motifs, subcellular localization, co-expression analysis, and RNA abundance data. We demonstrate that 18% of the proteins in the inventory have functions outside the plastid and/or beyond green tissues. Although 32% of proteins in the inventory have homologs in all cyanobacteria, unexpectedly, 30% are eukaryote-specific. Finally, 8% of the proteins of unknown function share no similarity to any characterized protein and are plant lineage-specific. We present this annotated inventory of 597 proteins as a resource for functional analyses of plant-specific biochemistry.
