Structural Biochemical and Mechanistic Studies of Two Novel and Versatile Archaeal Glucanotransferase cum Exoamylase Enzymes

Abstract

Carbohydrates constitute a large share of all the macromolecules found in nature. newlineThe study of their structure, function, and synthesis has increased in importance newlinegreatly in recent times, in the fields of both food and health. In the food industry, newlinemodified carbohydrates are in the limelight. In the health sector, the purpose, newlinefunction, and patterns of glycosylation of proteins are gaining importance. newlineModifications of carbohydrates are mainly carried out by carbohydrate-modifying newlineenzymes. Such enzymes have recently been classified and categorized on the newlinebasis of their similarities of sequence, in the CAZy database, and on the basis of newlinetheir functions in glycosidic bond cleavage, bond formation, debranching newlinefunctions, isomerization functions etc. The product of each of these enzyme newlinefunctions is essential at some stage of carbohydrate metabolism and, newlineconsequently, in the industry related to carbohydrates. This had led to the search newlinefor enzymes with new specificities, and features, involving the formation of newlineunique products, or versatile enzymes featuring multiple specificities or catalytic newlinefunctions. In particular, there is a focus on enzymatic functions that include both newlinethe breaking as well as synthesizing of glycosidic bonds, as glycosyl hydrolases newlineand as glycosyltransferases, respectively. Enzymes that perform these functions newlinetake part in various metabolic pathways, and are useful in the industry: in the newlinegeneration of sweeteners, novel dietary carbohydrates, etc., cosmetic industry: as newlinethickening agents, detergent industry, textile industry and with the recent newlineemphasis on generation and use of clean energy such enzymes find a huge role in newlineproduction of biofuels. newlineGlycosyl Hydrolases are enzymes that hydrolyze/break a glycosidic bond to newlinegenerate products smaller in size than the initial substrate. They include broadly newlineendo-acting enzymes as well as exo-acting enzymes to create a variety of newlineoligosaccharide species. Glycosyltransferases are enzymes that transfer newlinesugars/glucans from donor to acceptor molecules to p