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Updated: Jul 24, 2025

Single Liposome Measurements for the Study of Proton-Pumping Membrane Enzymes Using Electrochemistry and Fluorescent Microscopy
Published on: February 21, 2019
[Functional analysis of functional membrane microdomains in the biosynthesis of menaquinone-7]
Yajun Dong1, Shixiu Cui1,2, Yanfeng Liu1,2
1Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, Jiangsu, China.
Abstract:
Functional membrane microdomains (FMMs) that are mainly composed of scaffold proteins and polyisoprenoids play important roles in diverse cellular physiological processes in bacteria. The aim of this study was to identify the correlation between MK-7 and FMMs and then regulate the MK-7 biosynthesis through FMMs. Firstly, the relationship between FMMs and MK-7 on the cell membrane was determined by fluorescent labeling. Secondly, we demonstrated that MK-7 is a key polyisoprenoid component of FMMs by analyzing the changes in the content of MK-7 on cell membrane and the changes in the membrane order before and after destroying the integrity of FMMs. Subsequently, the subcellular localization of some key enzymes in MK-7 synthesis was explored by visual analysis, and the intracellular free pathway enzymes Fni, IspA, HepT and YuxO were localized to FMMs through FloA to achieve the compartmentalization of MK-7 synthesis pathway. Finally, a high MK-7 production strain BS3AT was successfully obtained. The production of MK-7 reached 300.3 mg/L in shake flask and 464.2 mg/L in 3 L fermenter.
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