The evolution of cyclodextrin glucanotransferase product specificity.
Cyclodextrin glucanotransferases (CGTases) have attracted major interest from industry due to their unique capacity of forming large quantities of cyclic alpha-(1,4)-linked oligosaccharides (cyclodextrins) from starch. CGTases produce a mixture of cyclodextrins from starch consisting of 6 (alpha), 7 (beta) and 8 (gamma) glucose units. In an effort to identify the structural factors contributing to the evolutionary diversification of product specificity amongst this group of enzymes, we selected nine CGTases from both mesophilic, thermophilic and hyperthermophilic organisms for comparative product analysis. These enzymes displayed considerable variation regarding thermostability, initial rates, percentage of substrate conversion and ratio of alpha-, beta- and gamma-cyclodextrins formed from starch. Sequence comparison of these CGTases revealed that specific incorporation and/or substitution of amino acids at the substrate binding sites, during the evolutionary progression of these enzymes, resulted in diversification of cyclodextrin product specificity.
Microbial Physiology, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Carbohydrate Bioprocessing, University of Groningen, Kerklaan 30, 9751 NN Haren, the Netherlands.
Ronan M
RM
Kelly
Lubbert
L
Dijkhuizen
Hans
H
Leemhuis
D000595:Amino Acid Sequence; D001419:Bacteria / Q000737:chemistry / Q000145:classification / Q000201:enzymology* / Q000235:genetics; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D003505:Cyclodextrins / Q000737:chemistry / Q000378:metabolism; D004795:Enzyme Stability; D019143:Evolution, Molecular; D005964:Glucosyltransferases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D013213:Starch / Q000737:chemistry / Q000378:metabolism; D013379:Substrate Specificity
D001426:Bacterial Proteins; D003505:Cyclodextrins; D013213:Starch; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase