七烯甲萘醌合成过程中关键蛋白的定位分析  

Localization analysis of key proteins during the synthesis of menaquinone-7

作　　者：陈奇 张智航 夏洪志 孙怡 金柯 吕雪芹 崔世修 刘龙 CHEN Qi;ZHANG Zhihang;XIA Hongzhi;SUN Yi;JIN Ke;LYU Xueqin;CUI Shixiu;LIU Long(Key Laboratory of Carbohydrate Chemistry and Biotechnology,Ministry of Education,Jiangnan University,Wuxi 214122,China;Science Center for Future Foods,Jiangnan University,Wuxi 214122,China;Richen Bioengineering Co.Ltd.,Nantong 226010,China)

机构地区：[1]江南大学,糖化学与生物技术教育部重点实验室,江苏无锡214122 [2]江南大学,未来食品中心,江苏无锡214122 [3]南通励成生物工程有限公司,江苏南通226010

出　　处：《食品与发酵工业》2023年第2期8-12,共5页Food and Fermentation Industries

基　　金：国家自然科学基金(31871784);国家重点研发计划(2018YFA0900300)。

摘　　要：七烯甲萘醌作为维生素K 2的重要亚型,在细胞中主要存在于细胞膜上,在氧化磷酸化的过程中起到电子载体的作用。作为七烯甲萘醌合成过程中的关键酶,1,4-二羟基-2-萘甲酸异戊二烯基转移酶(1,4-dihydroxy-2-naphthoic acid prenyltransferase,MenA)和甲基转移酶(methyltransferase,MenH)目前研究较少,其在细胞中的分布还未被研究,这也限制了七烯甲萘醌产量的进一步提高。该研究重点关注MenA和MenH在细胞内的分布问题,首先构建MenA、MenH和eGFP的融合蛋白,利用荧光定位的方法确定MenA和MenH在细胞中的定位。然后,使用表面活性剂Triton-100破坏细胞膜的结构,发现随着表面活性剂浓度的增加,七烯甲萘醌的合成受到明显抑制。该研究表明细胞膜结构的完整性是七烯甲萘醌合成的前提条件,并且揭示了七烯甲萘醌是在细胞膜上直接被合成,不是被转运到细胞膜中。研究结果为深入探索七烯甲萘醌合成机制提供了方向。As an important subtype of the fat-soluble vitamin K 2,menaquinone-7(MK-7)plays an important role in the prevention of cardiovascular sclerosis and the treatment of osteoporosis,due to the advantages of long half-life and high biological affinity in human body.Thus,MK-7 has attracted much attention in the fields of medicine and functional food.While studies have shown that MK-7 is a component of the cell membrane and acts as an electron carrier in electron transport,there were few reports on the mechanism of MK-7 entering and leaving the cell membrane.Although 1,4-dihydroxy-2-naphthoic acid prenyl transferase MenA and methyltransferase MenH were known to play an important role in the synthesis of MK-7,there was a lack of in-depth research on their distribution in cells,limiting the further increase in the production of MK-7.We determined the localization of MenA and MenH in cells by fluorescence labeling.Then,the surfactant Triton-100 was used to destroy the cell membrane structure to verify the effect of the integrity of the cell membrane on the synthesis of MK-7.When the concentration of Triton-100 in the fermentation medium was 0.1%,the synthesis of MK-7 was significantly inhibited.When the concentration of Triton-100 reached 0.5%,the synthesis of MK-7 could not be detected.This study reveals that the integrity of cell membrane structure is the prerequisite for the synthesis of MK-7,and MK-7 is synthesized directly on the cell membrane,which is not transported to the cell membrane.The research results provide a direction for in-depth exploration of the synthesis mechanism of menaquinone-7.

关 键 词：七烯甲萘醌 枯草芽孢杆菌 MENA MenH 细胞膜 定位 

分 类 号：TQ466.6[化学工程—制药化工]