A structural classification of carbohydrate epimerases: From mechanistic insights to practical applications.
In recent years, carbohydrate epimerases have attracted a lot of attention as efficient biocatalysts that can convert abundant sugars (e.g.d-fructose) directly into rare counterparts (e.g.d-psicose). Despite increased research activities, no review about these enzymes has been published in more than a decade, meaning that their full potential is hard to appreciate. Here, we present an overview of all known carbohydrate epimerases based on a classification in structural families, which links every substrate specificity to a well-defined reaction mechanism. The mechanism can even be predicted for enzymes that have not yet been characterized or that lack structural information. In this review, the different families are discussed in detail, both structurally and mechanistically, with special reference to recent examples in the literature. Furthermore, the value of understanding the reaction mechanism will be illustrated by making the link to possible application and engineering targets.
Centre for Industrial Biotechnology and Biocatalysis, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium.
Stevie
S
Van Overtveldt
Centre for Industrial Biotechnology and Biocatalysis, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium.
Tom
T
Verhaeghe
Bio-Prodict BV, Nieuwe Marktstraat 54E, 6511 AA, Nijmegen, The Netherlands.
Henk-Jan
HJ
Joosten
Bio-Prodict BV, Nieuwe Marktstraat 54E, 6511 AA, Nijmegen, The Netherlands.
Tom
T
van den Bergh
Centre for Industrial Biotechnology and Biocatalysis, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium.
Koen
K
Beerens
Centre for Industrial Biotechnology and Biocatalysis, Faculty of Bioscience Engineering, Ghent University, Coupure links 653, 9000 Gent, Belgium.
Tom
T
Desmet
D002238:Carbohydrate Epimerases / Q000737:chemistry* / Q000145:classification; D002241:Carbohydrates / Q000737:chemistry; D004798:Enzymes / Q000737:chemistry* / Q000145:classification; D011487:Protein Conformation; D013379:Substrate Specificity; D013696:Temperature
D002241:Carbohydrates; D004798:Enzymes; D002238:Carbohydrate Epimerases
Carbohydrate epimerases; Classification; Engineering opportunities; GalE; Mechanisms; Rare sugar synthesis; Structural family