title: Catalytic properties of endoxylanase fusion proteins from Neocallimastix frontalis and effect of immobilization onto metal-chelate matrix.
abstract: The production of hybrid enzymes with novel properties and the research for new methods for enzyme immobilization in bioreactors are of major interest in biotechnology. We report here the second part of a study concerning the improvement of the properties of the endoxylanase XYN3A4 from the anaerobic fungi Neocallimastix frontalis. The effects of gene fusion and immobilization on metal-chelate matrix are also compared for the reference enzymes XYN3, XYN3A, XYN4 used for the construction of the fusion protein XYN3A4. The influence of the metal ion in the immobilization process was first investigated and best immobilization yields were obtained with the Cu(II) ion whereas best coupling efficiencies were reached with the Ni(II) ion. It was also observed that XYN3, XYN3A and XYN34 had a lower rate of hydrolysis when immobilized on Ni(II)-IDA and more difficulties to accomodate small substrates than the soluble enzymes. Nevertheless, a major difference was noted during the hydrolysis of birchwood xylan and it appears that the reaction using the immobilized XYN3A4 chimeric enzyme leads to the accumulation of a specific product.
authors.affiliation: Laboratoire de Génie Enzymatique, UMR CNRS 5013, Université Claude Bernard Lyon I, Bât. 308-43, Bd du 11 Novembre 1918, 69622 Villeurbanne Cedex, France. mlaurent@metacrawler.com
authors.forename: Laurent
authors.initials: L
authors.lastname: Mesta
authors.forename: Alain
authors.initials: A
authors.lastname: Heyraud
authors.forename: Jean Paul
authors.initials: JP
authors.lastname: Joseleau
authors.forename: Pierre R
authors.initials: PR
authors.lastname: Coulet
mesh_terms: D002384:Catalysis; D002614:Chelating Agents; D043364:Endo-1,4-beta Xylanases; D004789:Enzyme Activation; D004800:Enzymes, Immobilized / Q000737:chemistry; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D008670:Metals / Q000737:chemistry*; D020088:Neocallimastix / Q000201:enzymology* / Q000235:genetics; D009532:Nickel / Q000737:chemistry; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000737:chemistry / Q000145:classification / Q000235:genetics; D013379:Substrate Specificity; D014162:Transfection / Q000379:methods; D014995:Xylosidases / Q000096:biosynthesis* / Q000737:chemistry* / Q000145:classification / Q000235:genetics
chemical_list: D002614:Chelating Agents; D004800:Enzymes, Immobilized; D008670:Metals; D011993:Recombinant Fusion Proteins; D009532:Nickel; D014995:Xylosidases; D043364:Endo-1,4-beta Xylanases