title: Overexpression, purification, crystallization and preliminary diffraction studies of the Protaminobacter rubrum sucrose isomerase SmuA.
abstract: Palatinose (isomaltulose, alpha-D-glucosylpyranosyl-1,6-D-fructofuranose), a nutritional and acariogenic reducing sugar, is industrially obtained from sucrose by using immobilized cells of Protaminobacter rubrum that produce the sucrose isomerase SmuA. The isomerization of sucrose catalyzed by this enzyme also results in the formation of trehalulose (alpha-D-glucosylpyranosyl-1,1-D-fructofuranose) in smaller amounts and glucose, fructose and eventually isomaltose as by-products, which lower the yield of the reaction and complicate the recovery of palatinose. The determination of the three-dimensional structure of SmuA will provide a basis for rational protein-engineering studies in order to optimize the industrial production of palatinose. A recombinant form of the 67.3 kDa SmuA enzyme has been crystallized in the native state by the vapour-diffusion method. Crystals belong to the orthorhombic space group P2(1)2(1)2(1), with unit-cell parameters a = 61.6, b = 81.4, c = 135.6 A, and diffract to 1.95 A resolution on a synchrotron-radiation source.
authors.affiliation: Laboratoire de BioCristallographie, Institut de Biologie et Chimie des Protéines, CNRS, Université Claude Bernard Lyon 1, UMR 5086, IFR 128 BioSciences Lyon-Gerland, F-69367 Lyon Cedex 07, France.
authors.forename: Stéphanie
authors.initials: S
authors.lastname: Ravaud
authors.forename: Hildegard
authors.initials: H
authors.lastname: Watzlawick
authors.forename: Richard
authors.initials: R
authors.lastname: Haser
authors.forename: Ralf
authors.initials: R
authors.lastname: Mattes
authors.forename: Nushin
authors.initials: N
authors.lastname: Aghajari
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification*; D003460:Crystallization; D018360:Crystallography, X-Ray / Q000379:methods; D004187:Disaccharides / Q000737:chemistry; D004789:Enzyme Activation; D004926:Escherichia coli / Q000235:genetics; D020563:Gammaproteobacteria / Q000201:enzymology* / Q000235:genetics; D005964:Glucosyltransferases / Q000096:biosynthesis / Q000235:genetics* / Q000302:isolation & purification*; D007534:Isomaltose / Q000031:analogs & derivatives / Q000096:biosynthesis / Q000138:chemical synthesis; D013395:Sucrose / Q000737:chemistry
chemical_list: D001426:Bacterial Proteins; D004187:Disaccharides; D013395:Sucrose; D007534:Isomaltose; D005964:Glucosyltransferases; C116853:sucrose isomerase; C042003:trehalulose; C008189:isomaltulose