聚唾液酸(PSA)是一种具有重要生物功能的高分子多糖,广泛存在于自然界和人体中。由于其低免疫原性和良好的生物降解性,PSA被认为是一种理想的药物控释材料。本研究以大肠杆菌K87为出发菌株,通过过表达Neu5AC合成路径中的关键基因neuD,...聚唾液酸(PSA)是一种具有重要生物功能的高分子多糖,广泛存在于自然界和人体中。由于其低免疫原性和良好的生物降解性,PSA被认为是一种理想的药物控释材料。本研究以大肠杆菌K87为出发菌株,通过过表达Neu5AC合成路径中的关键基因neuD,构建了高效合成PSA的基因工程菌株。通过摇瓶发酵和发酵罐发酵实验,验证了不同拷贝数neuD基因对PSA产量的影响。结果表明,高拷贝数表达载体能显著提高PSA的产量,其中E. coli K87-6菌株在5 L发酵罐中PSA产量达8.4 g/L,比出发菌株提高27%。本研究构建的高效合成PSA的基因工程菌株在工业生产中具有广泛的应用前景。Polysialic acid (PSA) is a high-molecular-weight polysaccharide with significant biological functions, widely found in nature and the human body. Due to its low immunogenicity and good biodegradability, PSA is considered an ideal material for drug delivery systems. In this study, Escherichia coli K87 was used as the starting strain to construct genetically engineered strains for efficient PSA production by overexpressing the key gene neuD in the Neu5AC synthesis pathway. The effects of different copy numbers of the neuD gene on PSA yield were verified through shake flask and fermenter experiments. The results showed that high-copy-number expression vectors significantly increased PSA yield, with the E. coli K87-6 strain achieving a PSA yield of 8.4 g/L in a 5 L fermenter, which is 27% higher than the starting strain. The genetically engineered strains constructed in this study have broad application prospects in industrial production.展开更多
唾液酸在人的细胞识别、分化、迁移和信号识别等重要生理活动中具有重要的作用。在其生理功能的发挥过程中,唾液酸转移酶是不可或缺的重要参与者,其将唾液酸转移到单糖或寡糖的末端,因而唾液酸转移酶被越来越多的研究者所关注。本论文...唾液酸在人的细胞识别、分化、迁移和信号识别等重要生理活动中具有重要的作用。在其生理功能的发挥过程中,唾液酸转移酶是不可或缺的重要参与者,其将唾液酸转移到单糖或寡糖的末端,因而唾液酸转移酶被越来越多的研究者所关注。本论文梳理了前期文献研究的主要成果,将从其来源、分类、结构、酶学性质以及催化机理等方面进行综述,以供研究者参考。Sialyltransferase plays an important role in important physiological activities, such as cell recognition, differentiation, migration, and signal recognition in humans. In the process of its physiological function, sialyltransferase is an indispensable and important participant. It transfers sialic acid to the end of monosaccharides or oligosaccharides, so sialyltransferase is receiving increasing attention from researchers. This paper reviews the main achievements of previous literature research, including their sources, classifications, structures, enzymatic properties, and catalytic mechanisms, for reference by researchers.展开更多
文摘聚唾液酸(PSA)是一种具有重要生物功能的高分子多糖,广泛存在于自然界和人体中。由于其低免疫原性和良好的生物降解性,PSA被认为是一种理想的药物控释材料。本研究以大肠杆菌K87为出发菌株,通过过表达Neu5AC合成路径中的关键基因neuD,构建了高效合成PSA的基因工程菌株。通过摇瓶发酵和发酵罐发酵实验,验证了不同拷贝数neuD基因对PSA产量的影响。结果表明,高拷贝数表达载体能显著提高PSA的产量,其中E. coli K87-6菌株在5 L发酵罐中PSA产量达8.4 g/L,比出发菌株提高27%。本研究构建的高效合成PSA的基因工程菌株在工业生产中具有广泛的应用前景。Polysialic acid (PSA) is a high-molecular-weight polysaccharide with significant biological functions, widely found in nature and the human body. Due to its low immunogenicity and good biodegradability, PSA is considered an ideal material for drug delivery systems. In this study, Escherichia coli K87 was used as the starting strain to construct genetically engineered strains for efficient PSA production by overexpressing the key gene neuD in the Neu5AC synthesis pathway. The effects of different copy numbers of the neuD gene on PSA yield were verified through shake flask and fermenter experiments. The results showed that high-copy-number expression vectors significantly increased PSA yield, with the E. coli K87-6 strain achieving a PSA yield of 8.4 g/L in a 5 L fermenter, which is 27% higher than the starting strain. The genetically engineered strains constructed in this study have broad application prospects in industrial production.
文摘唾液酸在人的细胞识别、分化、迁移和信号识别等重要生理活动中具有重要的作用。在其生理功能的发挥过程中,唾液酸转移酶是不可或缺的重要参与者,其将唾液酸转移到单糖或寡糖的末端,因而唾液酸转移酶被越来越多的研究者所关注。本论文梳理了前期文献研究的主要成果,将从其来源、分类、结构、酶学性质以及催化机理等方面进行综述,以供研究者参考。Sialyltransferase plays an important role in important physiological activities, such as cell recognition, differentiation, migration, and signal recognition in humans. In the process of its physiological function, sialyltransferase is an indispensable and important participant. It transfers sialic acid to the end of monosaccharides or oligosaccharides, so sialyltransferase is receiving increasing attention from researchers. This paper reviews the main achievements of previous literature research, including their sources, classifications, structures, enzymatic properties, and catalytic mechanisms, for reference by researchers.
