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作 者 ：陈思礼;王建林;张娟;周明

期 刊 ：武汉植物学研究 2008年 26卷 6期 页码：581-588

关键词：鱼腥藻PCC7120；藻蓝蛋白β亚基；藻红蛋白β亚基；裂合酶；

Keywords:Anabaena sp.PCC7120, β-subunit of phycocyanin, β-subunit of phycoerythrocyanin, Biliprotein lyase,

摘 要 ：通过BLAST软件分别对藻胆蛋白裂合酶(biliprotein lyase)编码基因cpcS和cpcT进行同源搜索分析,在鱼腥藻(Anabaena)PCC7120中获取了同源基因all5292和alr0647。同源分析发现,这两个基因所编码氨基酸序列与其相对应的裂合酶氨基酸序列相似程度分别达到53.4%和61.4%。随后,对这两个基因进行了初步研究。结果显示:All5292和Alr0647无论单独还是共同表达均没有裂合酶催化藻蓝胆素PCB结合到藻蓝蛋白(phycocyanin)或藻红蓝蛋白(phycoerythrocyanin)β亚基上的功能。通过在不同生理条件下对鱼腥藻PCC7120的培养,还对这两个基因的调控表达进行了初步的探索。结果表明:all5292和alr0647的表达与氮源的缺乏与否有联系,在氮胁迫条件下两个基因均进行了转录而在氮源充足的情况下则没有表达。

Abstract:Genes all5292 and alr0647 were obtained by BLAST comparison from the cyanobacterium,Anabaena sp.PCC7120.They are homologous to cpcS and cpcT encoding the biliprotein lyases.According to the homology analysis,the similarity of All5292 and CpcS was up to 53.4%,and that of All0647 and CpcT up to 61.4%.The functions of All5292 and Alr0647 were analyzed in vitro with a heterologous E.coli system with plasmids conferring biosynthesis of phycocyanobilin(PCB)and of the acceptor proteins,β-phycoerythrocyanin(PecB)or β-phycocyanin(CpcB).The products were evaluated with absorption spectra and fluorescence spectra.The results showed that no lyase activity was found in any case,although all5292 and/or alr0647 expressed in the heterologous E.coli system.Via analyses of the transcription of all5292 and alr0647 in Anabaena sp.PCC7120,it was found that all5292 and alr0647 were transcribed only under N-starved conditions.

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