羽衣甘蓝中一个突变型肉桂酸-4-羟化酶基因的克隆及分析  

Cloning and Sequence Analysis of a Mutation-type Cinnamate-4-hydroxylase Gene from Brassica oleracea L.var.acephala DC.

作　　者：陈安和[1] 李加纳[1] 柴友荣[1] 王瑞[1] 吕俊[1] 

机构地区：[1]西南大学农学与生物科技学院

出　　处：《园艺学报》2007年第4期915-922,共8页Acta Horticulturae Sinica

基　　金：国家自然科学基金重点项目(30330400);重庆市自然科学基金重点项目(8446)

摘　　要：以羽衣甘蓝为材料,克隆了全长2431bp的肉桂酸-4-羟化酶基因BoC4H。它有两个内含子,mRNA为1715bp,编码一个481个氨基酸的推导蛋白,与其它植物C4H有广泛同源性。它含有细胞色素P450保守域和特征基序,如血红素结合域、E-R-R三联体、含T的结合槽基序、酶正确定向必需的铰链基序。BoC4H具有C4H/CYP73A5的大部分特征性底物结合位点基序(SRSs)和酶活性位点残基,但与拟南芥等植物C4H相比其编码区3′发生了C2242单碱基缺失和相应移码,导致其蛋白C-末端缺失/变异了36个残基,SRS6基序和其上的活性位点残基也相应缺失,因此BoC4H可能无功能或活性低。BoC4H为膜蛋白,可能定位于内质网,其二级结构主要为α-螺旋和随机卷曲。Swiss-Model不能预测出其三级结构。甘蓝中存在一个至少由5个成员构成的C4H基因家族。A2 431-bp full-length cinnamate-4-hydroxylase gene, BoC4H, was cloned from Brassica oleracea L. vat. acephala DC. It contains 2 introns. Its mRNA is 1 715 bp, encoding a deduced 481-amino-acid polypeptide with wide homologies to C4Hs from other plants. It possesses cytochrome P450 conserved domains and motifs such as the haem-iron binding motif, the E - R - R triad, the T-containing binding pocket motif and the hinge motif necessary for optimal orientation of the enzyme. It also has most of the canonical C4H/ CYP73A5-featured substrate-recognition sites （SRSs） and active site residues. But owing to a single-base deletion at C2242 and subsequent frame shift within the 3＇coding region as compared with C4H genes from Arabidopsis thaliana and other plants, BoC4H shows a 36-aa deletion/variation at its C-terminus, and the SRS6 motif together with active site residues therein are absent. Thus BoC4H may be of no function or low activity. BoC4H is a membrane protein and is probably associated with endoplasmic reticulum. Its secondary structure is dominated by alpha helices and random coils. Swiss-Model could not predict its tertiary structure. B. oleracea contains a C4H gene family with at least 5 members.

关 键 词：羽衣甘蓝 克隆 肉桂酸-4-羟化酶(C4H) 突变 序列分析 

分 类 号：S635[农业科学—蔬菜学]