The Role of a Loop in the Non-catalytic Domain B on the Hydrolysis/Transglycosylation Specificity of the 4-α-Glucanotransferase from Thermotoga maritima

• DOI: 10.1007/s10930-023-10136-2
• Publication Date: 2023-07-18T20:24:23Z
• Authors: Alexey Llopiz; Marco A. Ramírez-...; Leticia Olvera; Wendy Xolalpa-Vil...; Nina Pastor; Gloria Saab-Rincon
• Keywords: Thermotoga maritima; Residue (chemistry)

Abstract The mechanism by which glycoside hydrolases control the reaction specificity through hydrolysis or transglycosylation is a key element embedded in their chemical structures. determinants of seem to be complex. We looked for structural differences domain B between 4-α-glucanotransferase from Thermotoga maritima ( Tm GTase) and α-amylase petrophila (Tp Amylase ) found longer loop former that extends towards active site carrying W residue at its tip. Based on these we constructed variants W131G partial deletion residues 120-124/128-131, showed 11.6 11.4-fold increased hydrolysis/transglycosylation (H/T) ratio relative WT protein, respectively. These had reduction maximum velocity reaction, while affinity maltose as acceptor was not substantially affected. Molecular dynamics simulations allow us rationalize increase H/T terms flexibility near conformations catalytic acid associated p Ka s.