Methods for screening and evaluation of antimicrobial activity of 18β-glycyrrhetinic acid binding to Escherichia coli outer membrane proteins
10.3760/cma.j.cn112309-20231225-00190
- VernacularTitle:靶向大肠埃希菌外膜蛋白的18β-甘草次酸的筛选及抗菌活性评价系统构建
- Author:
Xingyuan WANG
1
;
Qingrong LI
;
Xiaochen HAN
;
Xuyan ZHANG
;
Zhe WANG
;
Youcai QIN
;
Yindi CHU
;
Enguo FAN
Author Information
1. 中国医学科学院基础医学研究所北京协和医学院基础学院病原学系，北京 100005
- Keywords:
18β-glycyrrhetinic acid;
β-barrel assembly machinery complex;
In vitro recombination system
- From:
Chinese Journal of Microbiology and Immunology
2024;44(5):390-395
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To screen active antibacterial components from licorice extract using BamA and BamD, the core components of Escherichia coli ( E. coli) β-barrel assembly machinery (BAM), as targets in order to combat the increasingly serious problem of antibiotic resistance. Methods:Affinity ultrafiltration combined with high performance liquid chromatography-mass spectrometry (HPLC-MS) was used to screen the potential components interacting with BamA and BamD from licorice extract. Changes in the expression of bamA and bamD genes of E. coli after treatment with the compounds were detected by fluorescence quantitative PCR, and the effects of the compounds on the function of the BAM complex to integrate outer membrane proteins into the bacterial outer membrane were analyzed using an in vitro recombination system. The influence of the compounds on the integrity of bacterial membranes was evaluated through analyzing the accumulation of SDS within the bacterial cells. Results:Bioaffinity ultrafiltration combined with HPLC-MS screening revealed that 18β-glycyrrhetinic acid could interact with BamD. After 18β-glycyrrhetinic acid treatment, the expression of bamA gene increased by 1.5 times, and the expression of bamD gene increased by 2 times. However, the inhibitory effect of 18β-glycyrrhetinic acid on the membrane insertion function of the BAM complex was not observed in the in vitro recombinant system assay, and the cell membrane integrity assay experiments did not reveal any disruption of the E. coli cell membrane by 18β-glycyrrhetinic acid. Conclusions:Using BamA and BamD proteins as targets, a natural product screening method using affinity ultrafiltration combined with HPLC-MS is established. The screening result shows that 18β-glycyrrhetinic acid can interact with BamD and affect the expression of outer membrane proteins in E. coli. Therefore, the screening and experimental procedures established in this study are of good reference value for the screening of novel antimicrobial drugs from other sources targeting outer membrane proteins, and this study also suggests that the selection of the relevant target sites is crucial for the successful screening of the corresponding natural products.
