Thermodynamics of Ligand Binding to the Starch‐Binding Domain of Glucoamylase from Aspergillus Niger

53Citations
Citations of this article
13Readers
Mendeley users who have this article in their library.

This article is free to access.

Abstract

The thermodynamics of ligand binding to the starch‐binding domain (SBD) of glucoamylase from Aspergillus niger has been studied using titration calorimetry. The ligand binding was studied both with the SBD fragment as well as glucoamylase G1 which contains both a catalytic domain and SBD. The ligands were β‐cyclodextrin and three thiopanose analogues [panose =α‐d‐Glcp‐(l→6)‐α‐d‐Glcp‐(1→4)‐d‐Glcp] each including an α‐(1→6) thioglycosidic linkage at the non‐reducing end. β‐Cyclodextrin binds more strongly than the thiopanose analogues and these have a slightly increasing binding constant with chain length. The reactions are enthalpy‐driven with unfavourable contributions from entropy and the variations in enthalpy and entropy compensate each other linearly. SBD was shown to have two binding sites that appear to bind identically and independently in the isolated binding domain, whereas they interact with each other in a negatively cooperative fashion when the catalytic domain of glucoamylase is present (glucoamylase G1). In glucoamylase G1 one site of SBD has an increased binding constant compared to the SBD fragment, whereas the other has the same association constant. The change in binding constant and induced cooperativity were not due to interactions with the catalytic binding site, since binding of β‐cyclodextrin was the same both when the catalytic site was occupied by the strong inhibitor acarbose and when the catalytic site was free. Copyright © 1994, Wiley Blackwell. All rights reserved

Cite

CITATION STYLE

APA

Sigurskjold, B. W., Svensson, B., Williamson, G., & Driguez, H. (1994). Thermodynamics of Ligand Binding to the Starch‐Binding Domain of Glucoamylase from Aspergillus Niger. European Journal of Biochemistry, 225(1), 133–141. https://doi.org/10.1111/j.1432-1033.1994.00133.x

Register to see more suggestions

Mendeley helps you to discover research relevant for your work.

Already have an account?

Save time finding and organizing research with Mendeley

Sign up for free