Li Xiefei, Fan Xiankang, Shi Zihang, Xu Jue, Cao Yingying, Zhang Tao, Pan Daodong
State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-Products, Ningbo University, Ningbo, China.
Key Laboratory of Animal Protein Deep Processing Technology of Zhejiang, Ningbo University, Ningbo, China.
Front Microbiol. 2022 May 12;13:908145. doi: 10.3389/fmicb.2022.908145. eCollection 2022.
The function of the autoinducer-2 exporters (AI-2E) family transporter protein of is still unclear. The phylogenetic analysis was used to analyze the relationship between the AI-2E protein of the CICC 6074 strain and other AI-2E family members. KNabc strain was used to verify whether the protein has Na (Li)/H antiporter activity. The AI-2E protein overexpression strain was constructed by using the pMG36e expression vector, and the overexpression efficiency was determined by real-time quantitative PCR. The vitality and AI-2 activity of CICC 6074 strains were determined. The results showed that the AI-2E protein of formed a single branch on the phylogenetic tree and was closer to the AI-2E family members whose function was AI-2 exporter group I. The expression of AI-2E protein in the KNabc strain did not recover the resistance of the bacteria to the saline environment. Overexpression of AI-2E protein in CICC 6074 could promote the AI-2 secretion of CICC 6074 strain and enhance their survival ability in intestinal juice.
自诱导物-2 输出蛋白（AI-2E）家族转运蛋白的功能仍不清楚。利用系统发育分析来分析中国工业微生物菌种保藏管理中心（CICC）6074 菌株的 AI-2E 蛋白与其他 AI-2E 家族成员之间的关系。使用 KNabc 菌株来验证该蛋白是否具有 Na（Li）/H 反向转运活性。通过使用 pMG36e 表达载体构建 AI-2E 蛋白过表达菌株，并通过实时定量 PCR 测定过表达效率。测定了 CICC 6074 菌株的活力和 AI-2 活性。结果表明，该菌的 AI-2E 蛋白在系统发育树上形成一个单独的分支，并且与功能为 AI-2 输出蛋白 I 组的 AI-2E 家族成员关系更近。AI-2E 蛋白在 KNabc 菌株中的表达并未恢复该菌对盐环境的抗性。CICC 6074 中 AI-2E 蛋白的过表达可促进 CICC 6074 菌株的 AI-2 分泌，并增强其在肠液中的生存能力。
