摘要
为系统阐明金属抗菌肽SIF_(4)基于DNA拓扑异构酶靶点的非细胞质膜抑菌机理,以大肠杆菌为模式菌株,研究了金属抗菌肽SIF_(4)与基因组DNA的结合方式、对DNA拓扑异构酶I/II活性以及胞内核酸生物合成的影响机理。研究发现,金属抗菌肽SIF_(4)可能以类似溴化乙锭嵌插方式与基因组DNA结合,对拓扑异构酶I有较强抑制活性,但对拓扑异构酶II影响较小,可通过影响DNA负超螺旋解链和RNA聚合酶结合催化RNA转录过程发挥抑菌活性。研究还发现,经金属抗菌肽SIF_(4)处理12 h后,大肠杆菌胞内总DNA和总RNA生物合成量均受到不同程度的抑制,且呈现良好的量-效关系,1/2最小抑菌浓度(minimal inhibitory concentration,MIC)组与对照组(0 MIC)相比,胞内DNA和RNA生物量差异不显著(P>0.05),MIC和2 MIC组与对照组相比,胞内DNA和RNA生物量差异显著(P<0.05)。实验结果可为金抗肽SIF_(4)在食源性大肠杆菌生物防控中的应用提供理论支持。
To systematically elucidate how metal-binding antimicrobial peptide SIF_(4) exerts its antimicrobial activity by targeting DNA topoisomerase without destroying the cytoplasmic membrane,Escherichia coli was used as a model strain to investigate the binding mode of SIF_(4) with its genomic DNA and the impact of SIF_(4) on DNA topoisomerase I and II activities and intracellular nucleic acid biosynthesis.Results showed that SIF_(4) could bind to genomic DNA in a manner similar to ethidium bromide(EB)intercalation with strong inhibitory effect on topoisomerase I but weak effect on topoisomerase II,and catalyzed RNA transcription to exert antimicrobial activity by interfering with the unwinding of negative DNA supercoils and RNA polymerase binding.It was also found that the biosynthesis of intracellular DNA and RNA was inhibited to different degrees after 12 h treatment with SIF_(4),which exhibited a good dose-effect relationship.There was no significant difference in the amounts of intracellular DNA and RNA between the 1/2 minimum inhibitory concentration(MIC)group and the control group(P>0.05),but there was a significant difference between the MIC and 2 MIC groups and the control group(P<0.05).Our results may provide theoretical support for the application of SIF_(4) in the biocontrol of foodborne E.coli.
作者
李玉珍
肖怀秋
周慧恒
李篮
匡燕
刘淼
赵谋明
LI Yuzhen;XIAO Huaiqiu;ZHOU Huiheng;LI Lan;KUANG Yan;LIU Miao;ZHAO Mouming(School of Pharmaceutical and Bioengineering,Hunan Chemical Vocational Technology College,Zhuzhou 412000,China;School of Food Science and Engineering,South China University of Technology,Guangzhou 510000,China)
出处
《食品科学》
EI
CAS
CSCD
北大核心
2024年第2期149-154,共6页
Food Science
基金
湖南省自然科学基金科教联合基金项目(2022JJ60046)。
关键词
金属抗菌肽
大肠杆菌
拓扑异构酶
核酸
抗菌剂
metal-binding antimicrobial peptide
Escherichia coli
topoisomerase
nucleic acid
antimicrobial agent
