Functional characterization of a special thermophilic multifunctional amylase OPMA-N and its N-terminal domain

Abstract

A gene encoding a special thermophilic multifunctional amylase OPMA-N was cloned from Bacillus sp. ZW2531-1. OPMA-N has an additional 124-residue N-terminal domain compared with typical amylases and forms a relatively independent domain with a b-pleated sheet and random coil structure. Here we reported an unusual substrate and product specificities of OPMA-N and the impact of the additional N-terminal domain (1 -124 aa) on the function and properties of OPMA-N. Both OPMA-N (12.82 U/mg) and its N-terminal domain-truncated DOPMA-N (12.55 U/mg) only degraded starch to produce oligosaccharides including maltose, maltotriose, isomaltotriose, and isomaltotetraose, but not to produce glucose. Therefore, the N-terminal domain did not determine its substrate and product specificities that were probably regulated by its C-terminal b-pleated sheet structure. However, the N-terminal domain of OPMA-N seemed to modulate its catalytic feature, leading to the production of more isomaltotriose and less maltose, and it seemed to contribute to OPMA-N's thermostability since OPMA-N showed higher activity than DOPMA-N in a temperature range from 40 to 808 8 8 8 8C and the halflife (t1 2

Dimerization Mediates Thermo-Adaptation, Substrate Affinity and Transglycosylation in a Highly Thermostable Maltogenic Amylase of Geobacillus thermoleovorans

“…Modulators also exhibit similar effects on Gt-MamyT, as reported by Li et al [1] for the multifunctional amylase of Bacillus sp. ZW25311.…”

“…Fourthly, they can hydrolyze acarbose, a potent inhibitor of α-amylases, to produce glucose and acarviosine-glucose [pseudotrisacc-haride]. Maltogenic amylases are, therefore, known as multifunctional amylases [1].…”

Strain improvement studies on <i>Microbacterium foliorum</i> GA2 for production of α-amylase in solid state fermentation: Biochemical characteristics and wash performance analysis at low temperatures

“…In previous reports, similar results were also reported where Fe 2+ and Cu 2+ inhibited amylase activity (Alexsandro et al, 2011;Kikani and Singh, 2011;Li, S. et al, 2011;Lu et al, 2010). Ca 2+ independent a-amylase have also been reported by several authors (Kikani and Singh, 2011;Li, F. et al, 2011;Sindhu et al, 2011;Swain et al, 2006). All the tested inhibitors (EDTA, H 2 O 2 , CuSO 4 , Urea and SDS) in their highest concentrations were proved to be potent inhibitors for amylase except SDS.…”

Amy63, a novel type of marine bacterial multifunctional enzyme possessing amylase, agarase and carrageenase activities

“…Multifunctional enzymes (MFEs) are enzymes that are considered to perform multiple independent functions, and are often also moonlighting or promiscuous enzymes 1 2 3 4 5 . Moonlighting enzymes perform multiple autonomous and unrelated functions that are not due to gene fusions, multiple RNA splice variants, or pleiotropic effects 3 .…”