摘要
橡胶树ＨＭＧ－ＣＯＡ还原酶ｃＤＮＡ序列分析结果表明，该ｃＤＮＡ长段为１３８３ｂｐ，由此推导的氨基酸序列含有４６１个氨基酸残基。ＰＣＧＥＮＥ￣（ＴＭ）分析该ｃＤＮＡ克隆与拟南芥ＨＭＧ－ＣｏＡ还原酶ｃＤＮＡ序列同源性为７９．７％，氨基酸序列同源性为８０．２％，与苍鼠氨基酸序列同源性为５１％，与血吸虫氨基酸序列同源性为４８％。（１）发现ＨＭＧ－ｏｎＡ还原酶的一级结构在动物与植物之间存在较大的差异。（２）分析ＨＭＧ－ＣｏＡ还原酶的疏水性氨基酸图谱，发现橡胶树和拟南芥这两种植物权有１个跨膜势能区域（Ｄｏｍａｉｎ），而血吸虫、苍鼠、果蝇等几种动物却有７个跨膜势能区域，这说明该酶的二级结构在动植物之间也存在着较大的差异。（３）由于所分析的几种动植物ＨＭＧ－ＣｏＡ还原酶的羧基一端未见有疏水性区域，故推测具有疏水性区域Ｎ－端蛋白质与膜相结合，而酶的羧基端由于具有亲水性则起到酶的催化中心位点。（４）比较橡胶树ＨＭＧ－ＣｏＡ还原酶和拟南芥ＨＭＧ－ＣｏＡ还原酶氨基酸同源性，发现蛋白质（酶）的Ｎ－端氨基酸同源性较低，而靠近Ｃ－端同源性较高，这说明Ｃ－端部分较为保守，估计与酶的活性中心区域有关，而Ｎ－端同源性较差。
The cDNA sequence analysis of 3-hydroxy-3－methylglutaryl coenzyme A reductase inHevea brasiliensis shows the cDNA clone is 1383 bp long，and the deduced amino acids sequencelength consists of 461 amino acid residues. The cDNA sequence homology of HMG－CoA reduc-tase of Hevea is 79.7％when compared with Arabidopsis，and the amino acids sequence homolo-gy is 80．2％. The sequence homology between Hevea and hamster，human，Drosophila，andSchistosoma is 53．4％，52％，51％ and 48 ％ respectively by PCGENE^（TM）software.（1）Theamino acids sequence of Hevea and other plants and animals was analyzed．The primary structureof HMG－CoA reductase in plant is different from that in animal．（2）The Kyte hydrophobicityamino acid index plots analysis revealed that HMG－CoA reductase in the two plants（Hevea andArabidopsis）have only one potential transmembrane domain，but 7 in Schistosoma，hamster，human and Drosophila，Which shows the secondary structure of HMG－CoA reductase in plant isalso different from that in animal．（3）All the potential transmembrane domains（either in plantsor animals）are near to the amino terminus in HMG－CoA reducttqse，but the hydrophobicity do-mains are not found at the carboxyl terminus．So we deduce that the amino terminus of HMG-CoA reductase is bound to membrane，and carboxyl terminus may contain the active enzyme site.（4）Comparison of HMG－CoA reductase amino acid homology in Hevea and Arabidopsis revealsthat the N-terminus amino acid homology is lower than the COOH-terminal amino acids homolo-gy. This shows amino acid terminal is bound to different membrane. The HMG－CoA reductase inHevea is bound to lutoids membrane，and the HMG-CoA reductase in Arabidopsis is bound to mi-crosmal, mitochondria，endoplasmic reticulum and plastids.（5）Analysis of DNA replicate se-quence shows the cDNA gene of HMG－CoA reductase is more active in expression.
出处
《热带作物学报》
CSCD
1996年第2期5-10,共6页
Chinese Journal of Tropical Crops
基金
国家自然科学基金
关键词
橡胶树
还原酶
序列分析
基因结构
Hevea；3－hydroxy-3-methylglutaryl coenzyme A（HMG-CoA）reductase；Sequence
