Structural Biology: Biocatalysis Text Karl-Franzens-Universitaet Homepage of Karl Franzens Universität Graz Homepage of Institut für Chemie, Universität Graz
Home       Profile       Research       Funding       Publications       Staff       Alumni       Teaching      
header grafik
 
 
The term "industrial biocatalysis" denotes the use of enzymes as catalysts in chemical reactions leading to fine chemicals, which are then typically used for the production of pharmaceutical or agrochemical products. The use of enzymes is indicated when chiral products are desired due to the enzyme’s superb enantioselectivity.
Our research in this area was originally sterted within the Spezialforschungsbereich Biokatalyse, which was a nationally funded cooperative research initiative including several laboratories from the Technische Universität Graz and from the Karl Franzens Universität Graz. The SFB was followed by the "Competence Center Applied Biocatalysis". Our contribution to these collaborative research exercises has been to determine the 3D structures of potentially useful enzymes, followed by functional studies to elucidate the reaction mechanism. Recently, our funding sources have shifted to the national science foundation FWF
  Link to the homepage Competence Center Applied Biocatalysis


Link to the Austrian Science Foundation FWF



Hydroxynitrile lyases

  The chemical reaction catalyzed by hydroxynitrile lyases
Hydroxynitrile lyases catalyze the cleavage and formation of cyanohydrins. This process is used as a defense mechanism by a variety of plants, and it can be exploited in biotechnology for the enantioselective synthesis of chiral cyanohydrins. HNL's constitute an excellent example of convergent evolution, i.e. numerous HNL's have evolved independently from a variety of unrelated ancestors.
We were the first to elucidate the 3D structure of a hydroxynitrile lyase. The structure of the enzyme from Hevea brasiliensis revealed this enzymes to belong to the family of a /b hydrolases. The structures of numerous enzyme-inhibitor complexes analyzed in our laboratory have since then shed light on the controversial question of the enzymic mechanism. Meanwhile, we have also elucidated the 3D structures of other HNL's


Click here for a list of relevant publications
Section of the electron density of the high-resolution crystal structure of the hevea-HNL The 3D structure of the hevea-HNL
The 3D structure of the HNL from prunus amygdalus View on the active site of the structure of prunus amygdalus HNL



Hydrolaseas: Xylanases & Esterases

Xylanases degrade xylan in plant cell walls while leaving the cellulose fabric widely intact. These enzymes have found several biotechnological applications, specifically in pulp and paper processing, where they can be used as bleaching agents. We have determined the structure of the xylanases from Thermomyces lanuginosus and from Penicillium simplicissimum. Using a flash-freezing technique, we have also investigated complexes of the Penicillium enzyme with a series of linear and branched xylooligomers

The esterase EstB from Burkholderia gladioli belongs to a novel class of esterase with structural homology to b-lactamases. From the structure of a complex with the irreversible inhibitor diisopropyl fluorophosphate, the active-site nucleophile could be assigned. Modelling studies led to possible causes for the enzyme‘s lack of b -lactamase activity, in spite of 3D structural similarity.

Clic here for a list of relevant publications on xylanases and esterases
 
The xylanase from Penicillium simplicissimum: complexes with different ologoxylanes The xylanase from Penicillium simplicissimum: complexes with different ologoxylanes
The 3D structure of the esterase EstB from Burgholderia gladiolii The xylanase from Thermomycel lanuginosus
 
 
footer bild
Nov.15, 2004         Christoph.Kratky@uni-graz.at                                                            HOME              UNI GRAZ