中文摘要：

从迟缓爱德华氏菌（Edwarclsiellatarda）LSE40 fosmid文库克隆到编码寡肽透过酶的opp基因簇。该基因簇全长6741bp，含有5个ORF，依次编码OppA—B-C-D-F5个蛋白；位于oppA翻译起始住点上游385bp处有一个推测的转录起始位点，在该转录起点的-35和-10区分别有TAGACA和TATATT两个特征性启动子序列；位于oppA和oppB的间隔区和oppF之后的非编码区各有一个茎环结构，推测分别为oppA和opp基因簇的转录终止子。氨基酸序列分析表明该基因簇编码的各个蛋白与同属细菌鲶鱼爱德华氏菌（E．ictaluri）对应的各个蛋白高度相似，相似性在96％～98％；与其他革兰氏阴性菌相似性在56％～89％；与革兰氏阳性菌的相似性在27％～53％。以细菌OppA的保守结构域SBP_bac_5构建系统发生树，结果显示E．tardaLSE40与同属细菌E．ictaluri的亲缘关系最近，与肠杆菌科细菌的亲缘关系较近，与革兰氏阳性细菌的亲缘关系较远，表明oppA的SBP_bac_5结构域可作为细菌分类鉴定的依据。opp基因簇的获取为深入了解E．tarda适应环境和宿主的生存机制奠定了基础。

英文摘要：

The Oligopeptide Permease （opp） gene cluster was cloned from fosmid library of Edwardsiella tarda LSE40. The obtained opp gene cluster spanned 6 741 bp which contains five ORFs encoding five putative proteins, OppA, OppB, OppC, OppD and OppF, respectively. A putative transcriptional start site locates 385 bp upstream from the oppA start codon, and there are TATATT and TAGACA sequences at positions -10 and -35 from the transcriptional start site, respectively. Two potential stem-loop structures located in the spacer region between oppA and oppB, and at downstream of oppF, are presumed as the terminators of oppA and opp, respectively. Opp of E. tarda showed 96%-98% identities with E. ictaluri, 56 %-89% identities with other gram negative bacteria and 27 %-53 % identities with gram positive bacteria. Phylogenetic tree was constructed based on the OppA conserved domain SBP_bac_5. The results showed that E. tarda LSE40 is most closely related to E. ictaluri, closely related to other Enterobacteriaceae bacteria, and less related to gram positive bacteria, suggesting domain SBP_bac_5 of OppA can be used as a molecular marker in the bacterial identification. The obtained opp lays the foundation for studying the survival mechanisms that how E. tarda adapts to the environment and the host.