目的:原核表达5型腺病毒纤毛蛋白(Ad5fiber)和35型腺病毒纤毛蛋白(Ad35fiber),并对蛋白活性进行初步分析。方法:将重组质粒pET28a-Ad5 fiber和pET28a—Ad35 fiber转化入E.coliBL21(DE3),IPTG诱导表达后,经Ni—NTA凝胶珠亲和纯化,用SDS—PAGE鉴定纯化蛋白,并用蛋白竞争性实验验证纯化蛋白的活性。结果:转化溶原菌后能够表达目的蛋白,Ad35fiber蛋白对Ad5(5型腺病毒)感染无影响,只能阻断Ad5F35(5型腺病毒纤毛被替换为35型腺病毒纤毛的嵌合腺病毒)对细胞的感染;Ad5fiber蛋白对嵌合腺病毒Ad5F35感染无影响,只能抑制Ad5对细胞的感染。结论:成功表达具有生物活性的5型和35型腺病毒纤毛蛋白,为进一步研究嵌合腺病毒Ad5F35感染细胞的机制奠定基础。
Aim: To construct the prokaryotic expression vector for Ad5 fiber and Ad35 fiber genes, purify proteins and study the activity. Methods: Recombinant plasmid pET28a-Ad5 fiber and pET28a-Ad35 fiber were transformed into E. coli Bl21 (DE3) and the proteins expression were induced with IPTG. The expressed proteins Ad5 fiber and Ad35 fiber were purified by Ni2~ affinity chromatography and identified by SDS-PAGE. The bioactivity of proteins Ad5 fiber and Ad35 fiber were certificated by competitive binding method. Results: The proteins Ad5 fiber and Ad35 fiber can be detected in the supernatant. The proteins Ad5 fiber specifically inhibited the infectivity of the Ad5 virus in a dose-dependent manner, while had no effect on the Ad5F35- mediated gene transfer. The proteins Ad35 fiber blocked the Ad5F35-mediated gene transfer in a dose-dependent manner and had no effect on the infectivity of the Ad5 virus in competition experiments. Conclusion: Recombinant vectors Ad5 fiber and Ad35 fiber were constructed successfully. The proteins Ad5 fiber and Ad35 fiber could specifically bind with different receptors. The study will lay a foundation for the investigation on the mechanism of Ad5F35 infection.