@article {2113, title = {Plant surface lipid biosynthetic pathways and their utility for metabolic engineering of waxes and hydrocarbon biofuels}, journal = {Plant Journal}, volume = {54}, number = {4}, year = {2008}, note = {ISI Document Delivery No.: 299KRTimes Cited: 12Cited Reference Count: 122Jetter, Reinhard Kunst, Ljerka}, month = {May}, pages = {670-683}, type = {Review}, abstract = {Due to their unique physical properties, waxes are high-value materials that are used in a variety of industrial applications. They are generated by chemical synthesis, extracted from fossil sources, or harvested from a small number of plant and animal species. As a result, the diversity of chemical structures in commercial waxes is low and so are their yields. These limitations can be overcome by engineering of wax biosynthetic pathways in the seeds of high-yielding oil crops to produce designer waxes for specific industrial end uses. In this review, we first summarize the current knowledge regarding the genes and enzymes generating the chemical diversity of cuticular waxes that accumulate at the surfaces of primary plant organs. We then consider the potential of cuticle biosynthetic genes for biotechnological wax production, focusing on selected examples of wax ester chain lengths and isomers. Finally, we discuss the genes/enzymes of cuticular alkane biosynthesis and their potential in future metabolic engineering of plants for the production of renewable hydrocarbon fuels.}, keywords = {ARABIDOPSIS-THALIANA, BRASSICA-OLERACEA, chain lengths, CONDENSING ENZYME, CUTICULAR WAX, cuticular waxes, ECERIFERUM MUTANTS, EPICUTICULAR WAX, ESTERS, fatty acid elongation, FATTY ACYL-COENZYME, HYDROCARBONS, industrial products, LEAVES PISUM-SATIVUM, MOLECULAR CHARACTERIZATION, SACCHAROMYCES-CEREVISIAE}, isbn = {0960-7412}, url = {://000255755000012}, author = {Jetter, R. and Kunst, L.} } @article {1437, title = {Expanding the thioglycoligase strategy to the synthesis of alpha-linked thioglycosides allows structural investigation of the parent enzyme/substrate complex}, journal = {Journal of the American Chemical Society}, volume = {128}, number = {7}, year = {2006}, note = {ISI Document Delivery No.: 015PITimes Cited: 21Cited Reference Count: 12}, month = {Feb}, pages = {2202-2203}, type = {Article}, keywords = {ARCHAEON, DISEASE TYPE-II, IDENTIFICATION, MOLECULAR CHARACTERIZATION, MUTATIONS, PHENOTYPE}, isbn = {0002-7863}, url = {://000235562900024}, author = {Kim, Y. W. and Lovering, A. L. and Chen, H. M. and Kantner, T. and McIntosh, L. P. and Strynadka, N. C. J. and Withers, S. G.} } @article {859, title = {Active site residues and mechanism of UDP-glucose dehydrogenase}, journal = {European Journal of Biochemistry}, volume = {271}, number = {1}, year = {2004}, note = {ISI Document Delivery No.: 756CXTimes Cited: 16Cited Reference Count: 33}, month = {Jan}, pages = {14-22}, type = {Article}, abstract = {UDP-glucose dehydrogenase catalyzes the NAD(+)-dependent twofold oxidation of UDP-glucose to give UDP-glucuronic acid. A sequestered aldehyde intermediate is produced in the first oxidation step and a covalently bound thioester is produced in the second oxidation step. This work demonstrates that the Streptococcus pyogenes enzyme incorporates a single solvent-derived oxygen atom during catalysis and probably does not generate an imine intermediate. The reaction of UDP-[6",6"-di-H-2]-D-glucose is not accompanied by a primary kinetic isotope effect, indicating that hydride transfer is not rate determining in this reaction. Studies with a mutant of the key active site nucleophile, Cys260Ala, show that it is capable of both reducing the aldehyde intermediate, and oxidizing the hydrated form of the aldehyde intermediate but is incapable of oxidizing UDP-glucose to UDP-glucuronic acid. In the latter case, a ternary Cys260Ala/aldehyde intermediate/NADH complex is presumably formed, but it does not proceed to product as both release and hydration of the bound aldehyde occur slowly. A washout experiment demonstrates that the NADH in this ternary complex is not exchangeable with external NADH, indicating that dissociation only occurs after the addition of a nucleophile to the aldehyde carbonyl. Studies on Thr118Ala show that the value of k(cat) is reduced 160-fold by this mutation, and that the reaction of UDP-D-[6",6"-di-H-2]-glucose is now accompanied by a primary kinetic isotope effect. This indicates that the barriers for the hydride transfer steps have been selectively increased and supports a mechanism in which an ordered water molecule (H-bonded to Thr118) serves as the catalytic base in these steps.}, keywords = {ACID, ALDEHYDE DEHYDROGENASE, CONSERVED CYSTEINE RESIDUES, DEHYDROGENASE, ENZYME, GDP-MANNOSE DEHYDROGENASE, GROUP-A STREPTOCOCCI, HISTIDINOL, MOLECULAR CHARACTERIZATION, PSEUDOMONAS-AERUGINOSA, URIDINE DIPHOSPHOGLUCOSE DEHYDROGENASE}, isbn = {0014-2956}, url = {://000187449200002}, author = {Ge, X. and Penney, L. C. and van de Rijn, I. and Tanner, M. E.} } @article {4751, title = {The first structure of UDP-glucose dehydrogenase reveals the catalytic residues necessary for the two-fold oxidation}, journal = {Biochemistry}, volume = {39}, number = {23}, year = {2000}, note = {ISI Document Delivery No.: 324PRTimes Cited: 62Cited Reference Count: 49}, month = {Jun}, pages = {7012-7023}, type = {Article}, abstract = {Bacterial UDP-glucose dehydrogenase (UDPGlcDH) is essential for formation of the antiphagocytic capsule that protects many virulent bacteria such as Streptococcus pyrogenes and Streptococcus pneumoniae type 3 from the host{\textquoteright}s immune system. We have determined the X-ray structures of both native and Cys260Ser UDPGlcDH from S. pyogenes (74\% similarity to S. pneumoniae) in ternary complexes with UDP-xylose/NAD(+) and UDP-glucuronic acid/NAD(H), respectively. The 402 residue homodimeric UDPGlcDH is composed of an N-terminal NAD(+) dinucleotide binding domain and a C-terminal UDP-sugar binding domain connected by a long (48 Angstrom) central alpha-helix. The first 290 residues of UDPGlcDH share structural homology with 6-phosphogluconate dehydrogenase, including conservation of an active site lysine and asparagine that are implicated in the enzyme mechanism. Also proposed to participate in the catalytic mechanism are a threonine and a glutamate that hydrogen bond to a conserved active site water molecule suitably positioned for general acid/base catalysis.}, keywords = {alanine, ALIGNMENT, CRYSTAL-STRUCTURE, ESCHERICHIA-COLI, GROUP-A STREPTOCOCCI, INSIGHTS, MECHANISM, MOLECULAR CHARACTERIZATION, REDUCTASE, SUBSTRATE-BINDING}, isbn = {0006-2960}, url = {://000087631000031}, author = {Campbell, R. E. and Mosimann, S. C. and van de Rijn, I. and Tanner, M. E. and Strynadka, N. C. J.} } @article {4273, title = {Covalent adduct formation with a mutated enzyme: Evidence for a thioester intermediate in the reaction catalyzed by UDP-glucose dehydrogenase}, journal = {Journal of the American Chemical Society}, volume = {120}, number = {26}, year = {1998}, note = {ISI Document Delivery No.: ZZ420Times Cited: 15Cited Reference Count: 23}, month = {Jul}, pages = {6613-6614}, type = {Article}, keywords = {ALDEHYDE DEHYDROGENASE, biosynthesis, GENE, GROUP-A, HYALURONIC-ACID SYNTHESIS, INSERTION, MOLECULAR CHARACTERIZATION, MUTATIONS, PNEUMONIAE, STREPTOCOCCI, TYPE-3 CAPSULAR POLYSACCHARIDE}, isbn = {0002-7863}, url = {://000074727600028}, author = {Ge, X. and Campbell, R. E. and van de Rijn, I. and Tanner, M. E.} } @article {3922, title = {Properties and kinetic analysis of UDP-glucose dehydrogenase from group a streptococci - Irreversible inhibition by UDP-chloroacetol}, journal = {Journal of Biological Chemistry}, volume = {272}, number = {6}, year = {1997}, note = {ISI Document Delivery No.: WG192Times Cited: 39Cited Reference Count: 48}, month = {Feb}, pages = {3416-3422}, type = {Article}, abstract = {UDP-glucuronic acid is used by many pathogenic bacteria in the construction of an antiphagocytic capsule that is required for virulence. The enzyme UDP-glucose dehydrogenase catalyzes the NAD(+)-dependent 2-fold oxidation of UDP-glucose and provides a source of the acid. In the present study the recombinant dehydrogenase from group A streptococci has been purified and found to be active as a monomer. The enzyme contains no chromophoric cofactors, and its activity is unaffected by the presence of EDTA or carbonyl-trapping reagents. Initial velocity and product inhibition kinetic patterns are consistent with a bi-uni-uni-bi ping-pong mechanism in which UDP-glucose is bound first and UDP-glucuronate is released last. UDP-xylose was found to be a competitive inhibitor (K-i, 2.7 mu M) of the enzyme. The enzyme is irreversibly inactivated by uridine 5{\textquoteright}-diphosphate chloroacetol due to the alkylation of an active site cysteine thiol. The apparent second order rate constant for the inhibition (k(i)/K-i) was found to be 2 x 10(3) mM(-1) min(-1). Incubation with the truncated compound, chloroacetol phosphate, resulted in no detectable inactivation when tested under comparable conditions. This supports the notion that uridine 5{\textquoteright}-diphosphate-chloroacetol is bound in the place of UDP-glucose and is not simply acting as a nonspecific alkylating agent.}, keywords = {ALDEHYDE DEHYDROGENASE, BOVINE LIVER, CAPSULE, CONSERVED CYSTEINE RESIDUES, GROUP-A STREPTOCOCCI, HISTIDINOL DEHYDROGENASE, HYALURONIC-ACID SYNTHESIS, MOLECULAR CHARACTERIZATION, MUTAGENESIS, PNEUMONIAE, SITE-DIRECTED}, isbn = {0021-9258}, url = {://A1997WG19200045}, author = {Campbell, R. E. and Sala, R. F. and vandeRijn, I. V. and Tanner, M. E.} }