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本文用反向PCR方法扩增并分析了核盘菌arom基因,以研究核盘菌和其他真菌在该基因之间的进化关系,并为其编码蛋白(AROM)的催化机制研究、植物转基因和蛋白抑制剂设计提供基础.arom基因编码预分支酸芳香族氨基酸(苯丙氨酸、酪氨酸和色氨酸)合成途径中催化第二步到第六步的五功能多肽.序列分析表明核盘菌arom基因含有一个4773bp的编码框,无内含子.推测的蛋白序列含有1590个氨基酸,与已知的所有AROM蛋白同源.理论分子量(Mw)和等电点(pI)分别是172658.78D和6.45.核盘菌arom基因的GC%是44.94%.根据搜索二级数据库CDD和Prosite的结果表明该AROM蛋白含有五个保守结构域:脱氢奎尼酸合成酶结构域、脱氢奎尼酸脱水酶(脱氢奎尼酸酶)结构域、莽草酸脱氢酶结构域、莽草酸激酶结构域、5 -烯醇丙酮酰莽草酸-3-磷酸合成酶(EPSP合成酶)结构域和四个模式:两个EPSP合成酶模式、Ⅰ型脱氢奎尼酸酶活性位点模式和莽草酸激酶模式.通过比对和参照PIR 数据库显著位点规则发现核盘菌AROM蛋白含有四个保守碱基.在基因5′非翻译区-23和-77位置分别存在TATA盒和CAAT盒.在基因下游发现有两个位点可能是polyA加尾信号.另外还分析了arom基因的系统发育.图5参13.“,”An arom gene was cloned from genomic DNA of Scleortinia sclerotiorum by inverse PCR. The evolutionary relationships of S. sclerotiorum and other fungi in arom gene were studied. Results showed that the arom gene from of S. sclerotiorum has a single open reading frame of 4773 bp and does not include any introns. The derived amino acid sequence consists of 1590 residues, and it is homologous to all fungal AROM proteins studied so far. The theoretical isoelectric point (pI) and molecular weight (Mw) is 6.5 and 172.66 kD, respectively. GC percentage of the arom gene is 44.94. According to the results of searching from CDD and Prosite database, AROM protein of S. sclerotiorum contains five conserve domains: 3-dehydroquinate synthase domain, 3-dehydroquinate dehydratase (3-dehydroquinase) domain, shikimate 5-dehydrogenase domain, shikimate kinase domain, and -enolpyruvylshikimate-3-phosphate synthase (EPSP sythase) domain, and four motifs: two EPSP synthase signatures, dehydroquinase class I active site, shikimate kinase signature. According to the PIR Site Rule PIRSR000514-1, four functionally important amino acid residues are found by alignment. Putative TATA box and CAAT box locate separately in -23 and -77 loci in 5′ un-translated region, and two loci found in downstream arom gene are likely polyadenylation signals. In addition, phylogeny of arom gene is analyzed.