Carbohydrate Bioengineering
Interdisciplinary Approaches
By Tuula T. Teeri, Birte Svensson, Harry J. Gilbert, Ten FeiziThe Royal Society of Chemistry
Copyright © 2002 The Royal Society of Chemistry
All rights reserved.
ISBN: 978-0-85404-826-7Contents
1 Keynote Address,
Engineering Glycosidases for Constructive Purposes D.L. Jakeman and S.G. Withers, 3,
2 Structure-Function Studies of Carbohydrate-active Enzymes Structural Enzymology of Carbohydrate-active Enzymes G.J. Davies, 11,
Structural Evidence for Substrate Assisted Catalytic Mechanism of Bee Venom Hyaluronidase. a Major Allergen of Bee Venom Z. Marcovic-Housley and T. Schirmer, 19,
Structure and Function of Class α-1,2-Mannosidases Involved in Glycoprotein Biosynthesis A. Herscovics, F. Lipari, B. Sleno, P.A. Romero, F. Valée, P. Yip and P.L. Howell, 28,
Structure and Function of Lytic Transglycosylases from Pseudomonas aeruginosa N. T Blackburn and A. J. Clarke, 34,
Structural Studies of the Retaining Galactosyltransferase LGTC from Neisseria meningitidis K. Persson, H. Ly, M. Dickelmann, W. Wakarchuk, S. Withers and N. Strynadka, 42,
Amylosucrase, a Polyspecific Member of Family 13 with Unique Structural Features C. Albenne, O. Mirza, L. Skov, G. Potocki, R.-M. Willemot, P. Monsan, M. Gajhede and M. Remaud-Simeon, 49,
Three-dimensional Structure of Malto-oligosyl Trehalose Synthase M. Kobayashi, M. Kubota and Y. Matsuura, 57,
3 Protein Engineering of Carbohydrate-active Enzymes,
(Gluco)amylases, What Have We Learned So Far? B. Svensson, J. Sauer, H. Mori, M.T. Jensen, K.S. Bak-Jensenm, B. Kramhøft, N. Juge, J. Nøhr, L. Greffe, T.P. Frandsen, M.M. Placic, G. Williamson and H. Driguez, 67,
Increasing the Thermal Stability and Catalytic Activity of Aspergillus niger Glucoamylase by Combining Site Specific Mutations and Directed Evolution T.P. Frandsen, A. Svendsen, H. Pedersen, J. Vind and B. R. Nielsen, 76,
Cyclodextrin Glycosyltransferase as a Model Enzyme to Study the Reaction Mechanism of the α-Amylase Family J.C.M. Uitdehaag, L. Dijkhuizen and B. Dijkstra, 82,
4 Domain Structure and Engineering,
An Update on Carbohydrate Binding Modules H.J. Gilbert, D.N. Bolan, L. Szabo, H. Xie, M.P. Williamson, P.J. Simpson, S. Jamal, A.B. Boraston, D.G. Kilburn and R.A.J. Warren, 89,
Domain Fusion of α-Amylase and Cyclomaltodextrin Glucanotransferase K. Ohdan and T. Kuriki, 99,
Structure of the Catalytic Module and the Family 13 Carbohydrate Binding Module of a Family 10 Xylanase from Strepromyces olivaceoviridis in Complex with Xylose and Galactose Z. Fujimoto, A. Kuno, S. Kaneko, H. Kobayashi, I. Kusakabe and H. Mizuno, 106,
Designer Nanosomes: Selective Engineering of Dockerin-containing Enzymes into Chimeric Scaffoldins to Form Defined Nanoreactors H.-P. Fierobe, A. Mechaly, C. Tardif, A. Belaich, R. Lamed, Y. Shoham, J.-P. Belaich and E.A. Bayer, 113,
5 Chemo-enzymatic Carbohydrate Synthesis Chemi-enzymatic Synthesis of Toxin Binding Oligosaccharides Y.R. Fang, K. Sujino, A.S. Lu, J. Gregson, R. Yeske, V.P. Kamath, R.M. Ratcliff, M.J. Schur, W. W. Wakarchuk and M.M. Palcic, 127,
Engineering of Thermostable Family 1 β-glycosidases for Saccharide Processing T. Kaper, J. van der Oost and W.M. de Vos, 135,
The Xyloglucan-cellulose Network of Plant Cell Walls: A Prototype for the Chemoenzymatic Preparation of Novel Polysaccharide Composites W.S. York, M. Pauly, Q. Qin, Z. Jia, J.P. Simon, P. Albersheim and A. G. Dawill, 143,
6 Enzymology of Plant Cell Wall Carbohydrates,
Cellulose Synthesis and Engineering in Plants S. R. Turner, N. G. Taylor and P. Szyjanowicz, 153,
Studies on Plant Inhibitors of Pectin Modifying Enzymes: Polygalacturonase-inhibiting Protein (PGIP) and Pectin Methylesterase Inhibitor (PMEI) B. Mattei, A. Raiola, C. Caprari, L. Federici, D. Bellincampi, G. De Lorenzo, F. Cervone, A. Giovane and L. Camardella, 160,
7 Information Mining in Genomes and Glycomes,
Carbohydrate-active Enzymes in Completely Sequenced Genomes B. Henrissat and P.M. Coutinho, 171,
Recent Advances in Mycobacterial Arabinogalactan Biosynthesis in Post-genomics Era L. Kremer, L.G. Dover, S.S. Gurcha, A.K. Pathak, R.C. Reynolds and G.S. Besra, 178,
Neoglycolipid Technology – An Approach To Deciphering the Information Content of the Glycome T. Feizi, 186,
CHAPTER 1
Keynote Address
ENGINEERING GLYCOSIDASES FOR CONSTRUCTIVE PURPOSES
David L. Jakeman and Stephen G. Withers
Department of Chemistry, Protein Engineering Network of Centres of Excellence, University of British Columbia, Vancouver, Canada.
1 ABSTRACT
The synthesis of oligosaccharides using glycosidases as catalysts has been known for many years, but has been limited by the poor yields generally associated with such processes due to hydrolysis. Glycosynthases, mutant glycosidases in which the catalytic nucleophile has been replaced, offer an alternative form of catalyst that synthesizes glycosides from readily prepared glycosyl fluorides, but does not hydrolyze the glycoside products. The range of reactions performed by these enzymes is being extended through mutation of number of different glycosidases, as well as through random mutation of known glycosynthases, coupled with efficient screens.
2 DISCUSSION
Glycosidases have important roles as industrial catalysts for the breakdown of complex carbohydrates, yet their commercialization as catalysts for the synthesis of oligosaccharides has been less fruitful because the product is necessarily a substrate for hydrolysis by the wild-type enzyme. Despite the general lack of commercial success in exploiting glycosidases as catalysts for the synthesis of oligosaccharides, a diverse selection of glycosidases has been explored in the literature to perform transglycosylation reactions yielding oligosaccharides, and this area of research has been reviewed recently. There are many possible parameter permutations available to increase the yields of glycosidase-mediated transglycosylation, and for specific glycosidases respectable yields have been observed as a result of altering certain reaction conditions, but no one process has been universally successful in circumventing the hydrolysis conundrum and giving consistently high yields.
The mechanism of retaining glycosidases has been the study of intense research initially based upon Koshland's premise of a double-displacement occurring at the anomeric centre. Figure 1A shows the widely accepted reaction course for a retaining glycosidase hydrolyzing a substrate. Two active site carboxylic acid residues separated by approximately 5.5 Å apart act as a nucleophile and general acid / base catalyst respectively. Hydrolysis is initiated by attack of the nucleophile onto the anomeric carbon to form a covalent glycosyl-enzyme intermediate that in turn is hydrolyzed by an incoming water molecule to release enzyme and monosaccharide. The transglycosylation mechanism differs from the hydrolytic mechanism solely because a sugar residue replaces the water molecule attacking the covalent glycosyl enzyme-intermediate (Figure 1B). One approach taken to avoid hydrolysis of product from a transglycosylation reaction was the abolition of the first step of the hydrolytic reaction - by mutating the catalytic nucleophile to a non-nucleophilic residue. Whilst this approach does not permit formation of a covalent glycosyl-enzyme intermediate, an active site architecture is maintained that could...
