中文摘要：

从阴沟肠杆菌（Enterobacter cloacae）UW4菌株提取细菌总DNA，根据已报道的阴沟肠杆菌ACC脱氨酶（1-aminocyclopropane-1-carboxylic acid deaminase）基因序列设计简并引物，通过PCR扩增获得1条约1．02kb特异片段，把该片段连接到pGEM-T vector上进行测序。序列分析结果表明，该基因编码区全长为1017bp，共编码338个氨基酸残基，与报道的序列相比仅存在8个核苷酸的差异，同源性达99．1％；将其翻译成氨基酸序列后发现，仅引起了4个氨基酸残基的变化，氨基酸同源性为98．2％。利用DNASIS软件对蛋白质二级结构进行分析比较，发现其蛋白质二级结构及其单元与报道的序列完全一致。将其插入原核表达载体pET-28b进行诱导表达，发现其表达蛋白在分子量约39kD处比对照多出一明显条带；经Western blot分析检测，发现此带即为His-ACDS融合蛋白。

英文摘要：

A PCR product of 1.02 kb was obtained from the total DNA of Enterobacter cloacae UW4 strain, using oligonucleotide primers designed based on the reported sequence of 1-aminocyclopropane-1-carboxylic acid deaminase gene of Enterobacter cloacae. The product was ligated to pGEM-T vector and sequenced. Length of the coding region was 1 017 bp and encoded 338 amino acid residues. There were only eight nucleotide acids that were different from the reported sequence, and resulted in change of four amino acid residues, showing 99.1% of identity in nuclentide acids and 98.2% of identity in amino acids. Based on the analysis of using DNAsis, the cloned sequence had secondary structure and structure units of protein were completely same as that of the reported sequence. In addition, prokaryotic expression vector was constructed by inserting the cloned fragment into pET-28b and induced by IPTG, western blot result showed that the size of fusion protein expressed in this study coincided with that of foregone conclusion. These results implied a putative function of the newly cloned sequence identical to that of the reported gene sequence of ACC deaminasc.