title: Properties of a glycogen like polysaccharide produced by a mutant of Escherichia coli lacking glycogen synthase and maltodextrin phosphorylase.
abstract: Escherichia coli mutant TBP38 lacks glycogen synthase (GlgA) and maltodextrin phosphorylase (MalP). When grown on maltose in fed-batch fermentation TBP38 accumulated more than 50-fold higher glycogen-type polysaccharide than its parental strain. The polysaccharides were extracted at different growth stages and migrated as one peak in size-exclusion chromatography. TBP38 produced polysaccharides ranging 2.6 × 10(6)-4.6 × 10(6)Da. A ratio of short side-chains (DP ≦ 12) in the polysaccharides was greater than 50%, and number-average degree of polymerization varied from 9.8 to 8.4. The polysaccharides showed 70-290 times greater water-solubility than amylopectin. Km values using porcine and human pancreatic α-amylases with polysaccharides were 2- to 4-fold larger than that of amylopectin. kcat values were similar for both α-amylases. The TBP38 polysaccharides had 40-60% lower digestibility to amyloglucosidase than amylopectin. Intriguingly, the polysaccharides showed strong immunostimulating effects on mouse macrophage cell comparable to lipopolysaccharides. The lipopolysaccharide contamination levels were too low to account for this effect.
authors.affiliation: Department of Food Science and Technology, Chungnam National University, Daejeon 305-764, Republic of Korea.
authors.forename: Ji-Yun
authors.initials: JY
authors.lastname: Kwak
authors.affiliation: Department of Food and Biotechnology, Korea University, Sejong 339-700, Republic of Korea.
authors.forename: Min-Gyu
authors.initials: MG
authors.lastname: Kim
authors.affiliation: Department of Food and Biotechnology, Korea University, Sejong 339-700, Republic of Korea.
authors.forename: Young-Wan
authors.initials: YW
authors.lastname: Kim
authors.affiliation: Biomedical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Republic of Korea.
authors.forename: Hyun-Seung
authors.initials: HS
authors.lastname: Ban
authors.affiliation: Biomedical Genomics Research Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), Daejeon 305-806, Republic of Korea.
authors.forename: Mi-Sun
authors.initials: MS
authors.lastname: Won
authors.affiliation: Department of Food Science and Technology, Chungnam National University, Daejeon 305-764, Republic of Korea. Electronic address: jtpark@cnu.ac.kr.
authors.forename: Jong-Tae
authors.initials: JT
authors.lastname: Park
authors.affiliation: Department of Food Science and Biotechnology, Seoul National University, Seoul 151-921, Republic of Korea.
authors.forename: Kwan-Hwa
authors.initials: KH
authors.lastname: Park
mesh_terms: D000818:Animals; D002460:Cell Line; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D005964:Glucosyltransferases / Q000172:deficiency / Q000235:genetics*; D006006:Glycogen Synthase / Q000172:deficiency / Q000235:genetics*; D006868:Hydrolysis; D007155:Immunologic Factors / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects; D051379:Mice; D009154:Mutation; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000378:metabolism / Q000494:pharmacology
chemical_list: D007155:Immunologic Factors; D011135:Polysaccharides, Bacterial; D005964:Glucosyltransferases; C033938:maltodextrin phosphorylase; D006006:Glycogen Synthase
keywords: Amylase; Digestibility kinetics; Escherichia coli mutant; Glycogen; Immunostimulating effect; Intracellular polysaccharide; Water solubility