Bacterial sucrose isomerases: properties and structural studies

Abstract

Due to their significant role in food industry, sucrose isomerases are good candidates for rational protein engineering. Hence, specific modifications in order to modify substrate affinity and selectivity, product specificity but also to adapt their catalytic properties to particular industrial process conditions, is interesting. Our work on the structural studies of the sucrose isomerase, MutB, which presents the first structural data available on a trehalulose synthase and the first experimental data on complexed forms of sucrose isomerases represents a significant advance in the understanding of these enzymes. In this review we give an overview of what is known on biochemical properties and structural aspects of different sucrose isomerases in particular those reported from bacteria.

Transgenic expression of trehalulose synthase results in high concentrations of the sucrose isomer trehalulose in mature stems of field‐grown sugarcane

“…Sucrose isomerase (SI) enzymes can convert dissolved sucrose to isomers without any need for cofactors, and the conversion can be remarkably complete because of the multi‐step mechanism and the lower free energy of the isomers (Tewari and Goldberg, 1991; Veronese and Perlot, 1999; Zhang et al. , 2003; Rhimi et al. , 2008; Watzlawick and Mattes, 2009).…”

“…Use of sucrose isomers is currently limited by the expense of microbial or enzymatic conversion from more abundant, plant-derived sucrose (Schiweck et al, 1991). Sucrose isomerase (SI) enzymes can convert dissolved sucrose to isomers without any need for cofactors, and the conversion can be remarkably complete because of the multi-step mechanism and the lower free energy of the isomers (Tewari and Goldberg, 1991;Veronese and Perlot, 1999;Zhang et al, 2003;Rhimi et al, 2008;Watzlawick and Mattes, 2009). The known SI enzymes from various microbes are all in the same structural family (TIM-barrel family 13 glycosyltransferases), but they vary in kinetic efficiency and in product ratios, ranging from fairly specific isomaltulose (IM) or trehalulose (TH) synthases to mixed-isomer producers and hydrolases producing mostly hexoses from sucrose under certain conditions.…”

Mechanistic Analysis of Trehalose Synthase from Mycobacterium smegmatis

“…Presumably, these two hydrophobic clamps shield the active site during catalysis and suppress hydrolysis of the glucosyl-enzyme while the fructosyl residue rotates. Indeed, very few interactions are seen between the fructosyl moiety and the enzyme active site consistent with such mobility (54).…”

Isomaltulose production using free and immobilized Serratia plymuthica cells

“…Author(s) agree that this article remains permanently open access under the terms of the Creative Commons Attribution License 4.0 International License (Rhimi et al, 2008;Irwin and Strater, 1991). This alternative sugar is already used commercially in Japan as a sucrose replacement in the production of chocolate, chewing gum, cookies, drinks and pharmaceutical products (Rhimi et al, 2008;Kawaguti and Sato, 2010;Irwin and Strater, 1991). Also, isomaltulose, by hydrogenation, can be transformed into Isomalt  , a sugar-alcohol used as a dietetic non-cariogenic sweetener (Kroger et al, 2006;Kawaguti and Sato, 2010;Irwin and Strater, 1991).…”

“…Alternative sweeteners are used in noncariogenic and low-calorie food production, one segment of the food industry that is growing fastest (Kroger et al, 2006). It is a reducing sugar and a structural isomer of sucrose, naturally present in honey in small quantities (Rhimi et al, 2008;Kawaguti and Sato, 2010;Mundra et al, 2007). Isomaltulose is a low-cariogenic sugar (Hamada, 2002;Mundra et al, 2007), selectively promotes growth of beneficial bifido-bacteria among human intestinal microflora (Cummings et al, 2001;Birch and Wu, 2007) and it has a sweet taste and bulk similar to sucrose *Corresponding author.…”