Data from: Functional role and folding properties of the glucan-binding domain of oral bacterial glucansucrase

Streptococcus sobrinus glucansucrase transfers glucose from sucrose to
dextran and synthesizes water-insoluble glucan by creating α-1,3-branches
along the dextran polysaccharide. Glucansucrase contains a catalytic
domain and a glucan-binding domain (GBd) with six tandem repeats. We here
examined the role of GBd in the glucansucrase, focusing on its impact on
enzymatic activity, dextran binding, and structural stability. By
generating seven deletion mutants and a circularly permuted protein, our
research demonstrates that at least four GBd repeats and proper domain
orientation are required for efficient glucosyl transfer. Moreover,
circular dichroism and thermal unfolding analyses revealed that glucosyl
transfer efficiency is linked to cooperative interdomain folding rather
than dextran-binding affinity. These findings highlight the importance of
interdomain allostery in optimizing glucansucrase function.