决明查尔酮合成酶基因的克隆及序列分析

以决明(Cassia tora)为实验材料,利用RT-PCR和RACE技术,从决明嫩叶中克隆出查尔酮合成酶(Chal-one synthase,CHS)基因,其cDNA全长为1 459 bp,编码一个由390个氨基酸残基组成的多肽.氨基酸序列分析表明,决明CHS基因的氨基酸序列中含有44.61%的中性疏水氨基酸,29.74%的中性亲水氨基酸,12.56%的酸性氨基酸和13.O8%的碱性氨基酸.决明CHS基因的氨基酸序列中具有CHS家族酶系的氨基酸保守残基,包括结合底物CoA的结合残基及催化聚酮合成的催化残基,表明其可能参与聚酮化合物的合成.决明与其它植物CHS的氨基酸序列的进化分析表明,其与同为豆科决明属的翼叶决明(Cassia alata)的同源性较近,并且CHS家族可以分为CHS亚家族与非CHS亚家族.将得到的序列提交GenBank,登录号为EU430077.

Molecular Cloning and Analysis of a Chalone Synthase Gene of Cassia tora

Using Cassia tora as material,a cDNA encoding chalone synthase(CHS) was cloned from tender leaves of Cassia tora by RT-PCR and RACE.The full-length cDNA of CHS from Cassia tora had 1 459 bp with an open reading frame encoding 390 amino acids of protein.There were 44.61% of neutral hydrophobic residues,29.74% of neutral hydrophilic residues,12.56% of acid residues,and 13.08% of alkaline residues in the CHS amino acid sequence.It was suggested that the CHS from Cassia tora might be involved with the biosynthesis of polyketide since it maintained the same functional regions involved with CoA binding site and catalytic residues conserved in the CHS-superfamily enzymes.Furthermore,phylogenic analysis on the amino acid sequence of CHS from Cassia tora with other plants showed that Cassia tora was closely related to Cassia alata,and CHS-superfamily enzymes.They could be grouped into CHS-subfamily and non CHS-subfamily.The accession number of CHS from Cassia tora in GenBank was EU430077.