Exploring the novel mechanistic aspects of function of a hyperthermophile two-site exo-amylase-cum-glucanotransferase displaying substrate versatility

Abstract

We have recently described an exo-amylase-cum-glucanotransferase, PfuAmyGT, from Pyrococcus furiosus which uses disproportionation to generate a pool of glucose and small malto-oligosaccharides (MOGs) from starch, or from any single MOG (or a combination of MOGs). PfuAmyGT appears to use a combination of exo-amylase action and excision-and-transfer of glucose from donor to acceptor MOGs, using a unique and novel mechanism involving two catalytically-active sites (i.e., separate donor and acceptor sites, with a loop transferring the excised glucose) in place of the more common single site (at which the donated glucose is excised, and left, by the departing donor MOG, for being picked up by the acceptor MOG).