CYCLODEXTRIN GLYCOSYLTRANSFERASE PDF
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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The Application of Cyclodextrin Glycosyltransferase in Biological Science
CGTase is an enzyme common to many bacterial species, in particular of the Bacillus genus e. Second, we restricted functional comparisons to CGTase structures that were determined under identical experimental conditions, which warrants that all observed differences are ligand-induced.
Cereal Food World35, The isolated microorganism was submitted to the microscopical analysis and presented morphology compatible with an aerobic positive Gram bacilli, presented positive catalase and motility, being characterized as pertaining to the Bacillus genera. Reaction samples were removed at 0, 10, 20 and 30 min. From the x-ray structures it appears that in the maltononaose complex Tyr exposes, together with Phe, exposes a hydrophobic surface Fig.
Thermococcus sp CGTase presented an apparent molecular mass of 83 kDa 24 and one produced by Bacillus alkalophilic of Brazilian soil had molecular mass of CLIP enzymes are also more enantioselective than the native enzyme. Determination of the kinetic parameters. As expected, both mutants also showed lower affinities for cyclodextrins in the coupling reaction, and a reduced competitive product inhibition of the disproportionation reaction by cyclodextrins.
It is located far from the active site, at the interface of the A and D domains. Kinetic parameters Km and Vmax were estimated to be 1. 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 starch as substrate [ 20 ].
The situation is different when maltononaose-liganded CGTase is compared with unliganded CGTase root mean square deviation, 0.
AL-6 the molecular mass was 74 kDa 7 and 67 kDa for Bacillus sp.
To identify amino acids involved in cyclization, we studied their degree of evolutionary conservation in the active site Table I. Both mutants also provide valuable information about the processes taking place during cyclodextrin production assays. In the first step, the enzyme is derivatized with itaconic acid anhydride and then imprinted with ligands such as substrate analogs or inhibitors in aqueous medium [ 2627 ].
Large ring cyclodextrins could be synthesized by CGTase. CGTase that can synthesize fyclodextrin one type of CD has commercial importance since the separation of a particular form of CD is expensive and time-consuming.
Two membranes were used, kDa and 30 kDa, and four protein fractions were obtained: Data and refinement statistics are given in Table II. Ciclodextrina glicosiltransferase EC 2. Glucose and amylose, on the other hand, acted as synthesis repressors.
Our analysis of the structures of B. Furthermore, the results showed that the sample of MW inferior to kDa presented only one protein band with enzymatic activity, showing the purification by this process.
Cyclodextrin glycosyltransferase – Wikipedia
Kinetic data suggest that this is the rate-limiting step in the cyclization reaction. These results suggest that CGTase presents MW near to kDa, since a small amount of enzyme was filtered and another part was retained in the kDa membrane glycosyltransferxse the centrifugation.
In addition, the loop —, which contains the important residue Tyr, shows a maximal shift of 0. Thus, the starch chain bound to the MBSs does not have to move far to allow ring closure. Industrial potential of cyclodextrin glycosyl transferases. But there was such a limitation of YW that the mutation decreased the absolute CD 8 formation rate [ 25 ]. Related Content Load related web page information.
The conformation glycosyltransferasf Arg in both structures differs from wild type, unliganded CGTase not shown. All other residues, the third class, are those typical for CGTase bold in Table I and, therefore, are potentially involved in cyclization.
Both samples of MW inferior and superior to kDa presented halo formation. A distinctive feature of CGTases is the existence of the so-called cyclization axis generally an aromatic residue, either Phe or Tyr which is crutial for cyclodextrin formation. Dry derivatized enzyme and CD 8 were dissolved in potassium phosphate buffer.
August 25, ; Accepted Date: This could further limit unwanted hydrolysis and disproportionation reactions of small oligosaccharide chains in CGTase. This hydrogen bond to the substrate agrees better with the role of His as found from mutagenesis studies 3 Alternatively at MBS1 the bound starch chain may be replaced by another chain at any time glycosyltrqnsferase the reaction, without affecting the reaction taking place in the active site.
Based on these results, they put forward a new model for the action cycloeextrin CGTase on amylose. Km value of 1. Electrophoresis6, All of the CGTases can catalyze up to four reactions: