The Cyclization Mechanism of Cyclodextrin Glycosyltransferase (CGTase) as Revealed by a γ-Cyclodextrin-CGTase Complex at Å. Cyclodextrin glycosyltransferase is an important enzyme of cyclodextrin synthesis . This article mainly discusses the recent progress of the application of. INDUSTRIAL MICROBIOLOGY. Cyclodextrin glycosyltransferase from Bacillus licheniformis: optimization of production and its properties. Cyclodextrina.
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Cyclomaltodextrin glucanotransferase from Bacillus circulans E The xyclodextrin part of the donor substrate has to dissociate from the active site before the acceptor substrate can bind at these acceptor subsites Figure 2A [ 24 ]. The mechanism of cyclization has been extensively studied to gain insight into the factors that determine the substrate specificity of the enzyme and the reaction type specificity and to improve CGTase for industrial applications.
Halfway through refinement we observed density for a MPD molecule near residues Pro and Arg, which was included in the model using stereochemical parameters from the hetero compounds data base G. CGTase is ycclodextrin enzyme common to many bacterial species, in particular of the Bacillus genus e. Therefore, comparison of both structures can give useful insight into the mechanism of cyclization. Thus Phe stimulates the use of a circularized sugar chain as the acceptor instead of a free sugar.
This hydrogen bond to the substrate agrees better with the role of His as found from mutagenesis studies 3 Both structures were determined under experimentally identical conditions.
Possibly, Phe is correctly positioned to guide the circularizing movement of the linear chain toward the acceptor sites. All the contents of glhcosyltransferase journal, except where otherwise noted, is licensed under a Creative Commons Attribution License.
These data are similar to those reported from Tsai et al. This feature is very promising for the industrial application of CGTase enzymes with improved product specificity [ 24 ]. Views Read Cyclovextrin View history. Km and Vmax were estimated to be 1.
The cyclodextrin glucose O6 atom is at a 3. All these loops are intimately connected through various interactions. Disproportionation is very similar to coupling, but the cleaved dextrin is not a cyclodextrin, but a linear oligosaccharide that is then joined to a second oligosaccharide.
The conformation of Arg in both structures differs from wild type, unliganded CGTase not shown. Another hypothesis is the presence of more than one enzyme with CGTase activity, as demonstrated in Fig. Further evidence for a random cleavage of soluble starch by CGTase similar to an endo-type of attack has also been provided using fluorescent-labelled glycosyltransferrase as substrate [ 20 ].
Here we present the 1. Production of cyclodextrin from starch by cyclodextrin glycosyltransferase from Bacillus firmus and characterization of purified enzyme. Thereafter it was frozen under a cold nitrogen stream K for data collection using the soaking solution as cryo-protectant. The yield of LR-CDs could be controlled by the temperature of the synthesis reaction which was probably inhibiting the hydrolysis and coupling activity compared to the cyclization activity.
This is the first time that Arg is implicated in direct sugar binding. Identification of the CGTase in polyacrylamide gel. Purification and properties of cyclomaltodextrinase from alkalophilic Bacillus sp. Method and application to human serum proteins.
Cyclodextrin glycosyltransferase – Wikipedia
Industrial potential of cyclodextrin glycosyl transferases.
The Km and Vmax values were estimated using the Eadie-Hofstee plot. However, it is unknown how CGTase binds a cyclodextrin product. CrossRef Medline Google Scholar. Of particular importance is the centrally located residue Tyr, as was demonstrated in at least 6 different CGTases Table I. Furthermore, they are insoluble and can be separated and recycled many times, increasing their productivity [ 28 ].
Our analysis of the structures of B. Biosynthesis of cyclodextrin glucosyltransferase by immobilized Bacillusamyloliquefaciens in batch and continuos cultures. In addition, the loop —, which contains the important residue Tyr, shows a maximal shift of 0. Through these applications, the cyclodextrin glycosyltransferase will develop a great contribution to the new type of CD synthesis research area.
Both mutants also provide valuable information about the processes taking place during cyclodextrin production assays. This article mainly discusses the recent progress of the application of cyclodextrin glycosyltransferase in biological science. Nature, A detailed history of the development of cyclodextrins up to was reviewed by French 6.