采用PCR方法扩增嗜水气单胞菌(Aeromonas hydrophila)外膜蛋白相关基因,即粘附素(Aha)、外膜蛋白A(OmpA)基因全长序列,进行DNA测序及生物信息学分析。结果表明:Aha基因长1 314 bp,推导编码355 aa,5~24 aa区域为跨膜螺旋,26~355 aa区域为革兰氏阴性菌孔蛋白结构域(PF00267),Aha蛋白三级结构与模板(PDB:1PHO_A)相似性达28.21%;OmpA基因长1 102 bp,推导编码338 aa,含有OmpA跨膜结构域(PF01389)和OmpA结构域(PF00691),预测OmpA蛋白抗原表位位于64~69 aa、160~171 aa、244~249 aa、259~274 aa和295~301 aa区域,OmpA蛋白三级结构OmpA跨膜结构域和OmpA结构域与模板(PDB:1BXW_A,PDB:4ERH_A)相似性分别为27.45%和57.58%;进一步采用拉马钱德兰图(Ramachandran plot)检测分析,与Aha、OmpA基因蛋白三级结构预测结果一致。本研究有助于理解嗜水气单胞菌致病的分子机制,为鱼类疾病防治及疫苗应用提供科学参考。
Two outer membrane protein-related genes from the Zfl strain of A eromonas hydrophila, including adhesion (Aha) gene and outer membrane protein A (OmpA) gene, were amplified by PCR and the structure of them were then analyzed by bioinformatics methods. The results showed that the A ha gene sequence was 1 314 bp long, encoding a protein of 355 amino acids which has a transmembrane helix position (5-24) and gram-negative porin domain (PF00267); the OmpA gene sequence was 1 102 bp long, encoding a protein of 338 amino acids which has OmpA-like transmembrane domain (PF01389) and OmpA domain (PF00691). Moreover, the antigenic epitopes of OmpA protein were predicted to be located in the five regions (ie: 64-69, 160-171,244-249, 259-274 and 295-301). Homology modeling was used to construct 3D structure of Aha protein with the standard model (PDB: 1PHO_A) and OmpA protein with the known crystal 3D structure (PDB: 1BXW_A & PDB: 4ERH_A), respectively. In conclusion, these results help to understand the molecular mechanisms of A eromonas hydrophila pathogenesis, which will provide a scientific reference for the prevention and treatment offish diseases and vaccine applications.