Role of N-Terminal Extensional Long α-Helix in the Arylesterase from Lacticaseibacillus rhamnosus GG on Catalysis and Stability

In the α/β hydrolases superfamily, extra module modulated enzymatic activity, substrate specificity, and stability. The functional role of N-terminal extensional long α-helix (Ala2-Glu29, designated as NEL-helix) acting in arylesterase LggEst from Lacticaseibacillus rhamnosus GG had been systemically investigated by deletion mutagenesis, biochemical characterization, biophysical methods. NEL-helix did not change overall structure this arylesterase. led to shifting optimal pH into acidity loss thermophilic activity. produced a 10.6-fold drop catalytic activity towards best pNPC10. NEL-Helix was crucial for thermostability, chemical resistance, organic solvents tolerance. rigidity enzyme only reduced local active site. Sodium deoxycholate might partially replenish caused NEL-helix. Our research further enriched on catalysis stability hydrolase fold superfamily.