中文摘要：

以‘红肉脐橙’（Citrussinensis Osbeck ‘Cara Cara’）果实中分离的mRNA为模板,经RT-PCR扩增到约1.6kb的番茄红素β-环化酶（lycopene β-cyclase,Lcyb）cDNA片段。序列分析表明,该cDNA长1654bp,包含两个转录本Lcyb1和Lcyb2,最大开放读码框均为1512bp,可编码504个氨基酸。通过PCR方法获得红肉脐橙Lcyb1和Lcyb2cDNA编码区全长,构建了Lcyb1和Lcyb2的原核表达载体pET-CitL-cyb1和pET-CitLcyb2,并通过颜色互补试验证实表达的融合蛋白6×His-Lcyb1和6×His-Lcyb2均可将番茄红素转化为β-胡萝卜素。

英文摘要：

Using the mRNA from the fruit of Citrus sinensis Osbeck ＇ Cara Cara＇ as the template, we amplified and cloned the cDNA of lycopene β-cyclase gene by reverse transcription polymerse chain reactin （RTPCR）. Sequence analysis indicated that the cDNA was 1 654 bp long with two transcripts Lcybl and Lcyb2, which had an open reading frame of 1 512 bp and encoded a protein of 504 amino acids respectively. The fulllength coding region of Lcybl and Lcyb2 cDNA were cloned using PCR and further subcloned into pET-28a （ ＋ ）, resulting in the prokaryotic expression vector pET-CitLcybl and pET-CitLcyb2. The results of color complementation demonstrated fusion protein 6 x His-Lcybl and 6 x His-Lcyb2 could catalyse lycopene to form β-carotene respectively.