title: Biochemical characterization and functional analysis of UDP-glucose dehydrogenase, in the synthesis of biopolymer Ss from Sphingomonas sanxanigenens NX02.
abstract: Biopolymer Ss of Sphingomonas sanxanigenens strain NX02 is an sphingan that can be extracted using a small quantity of acid, which is a low cost extraction process. A UDP-glucose dehydrogenase gene (ugdG), related to Ss biosynthesis, was cloned from S. sanxanigenens NX02 and expressed in Escherichia coli. It encoded a 454-residue protein of 48.2 kDa. The deduced amino acid sequence had 77% identity with UDP-glucose dehydrogenase (UgdG) from Sphingomonas sp. KC8, and 73% identity with UgdG from Sphingomonas elodea ATCC31461. Purified recombinant UgdG had maximum activity at 35°C and pH 8.0, with Km values of 0.47 and 0.38 mM for UDP-glucose and NAD+, respectively. Overexpression of the ugdG gene in S. sanxanigenens resulted in increased (14.9 ± 0.5)% Ss production and higher fermentation broth viscosity. Furthermore, the weight-average molecular weight of polymer Ss from the recombinant strain was (5.3 ± 0.16)% higher and the viscosity was (74 ± 0.15)% higher than those from the WT strain at a shear rate of 1 rev/min.
authors.forename: M-M
authors.initials: MM
authors.lastname: Wu
authors.forename: H-D
authors.initials: HD
authors.lastname: Huang
authors.forename: G-Q
authors.initials: GQ
authors.lastname: Li
authors.forename: J-F
authors.initials: JF
authors.lastname: Zhou
authors.forename: T
authors.initials: T
authors.lastname: Ma
mesh_terms: D000596:Amino Acids / Q000235:genetics; D001704:Biopolymers / Q000096:biosynthesis*; D003001:Cloning, Molecular; D015964:Gene Expression Regulation, Bacterial; D007700:Kinetics; D010802:Phylogeny; D016415:Sequence Alignment; D020539:Sequence Analysis, Protein; D020578:Sphingomonas / Q000201:enzymology*; D014533:Uridine Diphosphate Glucose Dehydrogenase / Q000096:biosynthesis / Q000737:chemistry / Q000235:genetics*
chemical_list: D000596:Amino Acids; D001704:Biopolymers; D014533:Uridine Diphosphate Glucose Dehydrogenase