Dataset Information

Acceptor dependent catalytic properties of GH57 4-α-glucanotransferase from Pyrococcus sp. ST04.

ABSTRACT: The 4-α-glucanotransferase (4-α-GTase or amylomaltase) is an essential enzyme in maltodextrin metabolism. Generally, most bacterial 4-α-GTase is classified into glycoside hydrolase (GH) family 77. However, hyperthermophiles have unique 4-α-GTases belonging to GH family 57. These enzymes are the main amylolytic protein in hyperthermophiles, but their mode of action in maltooligosaccharide utilization is poorly understood. In the present study, we investigated the catalytic properties of 4-α-GTase from the hyperthermophile Pyrococcus sp. ST04 (PSGT) in the presence of maltooligosaccharides of various lengths. Unlike 4-α-GTases in GH family 77, GH family 57 PSGT produced maltotriose in the early stage of reaction and preferred maltose and maltotriose over glucose as the acceptor. The kinetic analysis showed that maltotriose had the lowest KM value, which increased amylose degradation activity by 18.3-fold. Structural models of PSGT based on molecular dynamic simulation revealed two aromatic amino acids interacting with the substrate at the +2 and +3 binding sites, and the mutational study demonstrated they play a critical role in maltotriose binding. These results clarify the mode of action in carbohydrate utilization and explain acceptor binding mechanism of GH57 family 4-α-GTases in hyperthermophilic archaea.

SUBMITTER: Jung JH

PROVIDER: S-EPMC9582752 | biostudies-literature | 2022

REPOSITORIES: biostudies-literature

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Acceptor dependent catalytic properties of GH57 4-α-glucanotransferase from <i>Pyrococcus</i> sp. ST04.

Jung Jong-Hyun JH Hong Seungpyo S Jeon Eun Jung EJ Kim Min-Kyu MK Seo Dong-Ho DH Woo Eui-Jeon EJ Holden James F JF Park Cheon-Seok CS

Frontiers in microbiology 20221006

The 4-α-glucanotransferase (4-α-GTase or amylomaltase) is an essential enzyme in maltodextrin metabolism. Generally, most bacterial 4-α-GTase is classified into glycoside hydrolase (GH) family 77. However, hyperthermophiles have unique 4-α-GTases belonging to GH family 57. These enzymes are the main amylolytic protein in hyperthermophiles, but their mode of action in maltooligosaccharide utilization is poorly understood. In the present study, we investigated the catalytic properties of 4-α-GTase ...[more]

PMID: 36274706

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Project description:In order to develop new organic materials for optoelectronic applications, a fundamental understanding of the electronic properties of specific chromophore combinations must be realized. To that end, we report "model" acceptor (A)-acceptor' (A')-acceptor (A) triads in which the pendants (A') we selected are well-known components of organic optoelectronic applications. Our pendants are sandwiched between two dialkoxyphenazine (A) through an alkyne bond. The A' was systematically increased in electron-deficiency from benzothiadiazole (BTD-P) to naphthalene diimide with octyl (NDI-O-P) or ethylhexyl groups (NDI-EH-P) to perylene diimide with ethylhexyl (PTCDI-EH-P) to assess changes in the electronic properties of the resultant molecules. Characterizations were performed using both experimental and theoretical methods. From optical and cyclic voltammetry, we found that the electron deficiency of each pendant was directly correlated to the energy level of the lowest unoccupied molecular orbital (E LUMO). When examining the simple molecular orbital diagrams produced at the B3LYP/6-31G* level of theory, the LUMOs were, as expected, primarily localized on the more electron-deficient pendants. In terms of the energy level of the highest occupied molecular orbital (E HOMO), the numerical values obtained experimentally also correlated with values obtained computationally. Attempting to construct a simplified model that would explain these correlated values was not as readily apparent, given the disparate physical characteristics of these compounds. For example, BTD-P and NDI-O-P/NDI-EH-P achieved planarity when computationally optimized, but PTCDI-EH-P adapted a "buckled" geometry on the central PTCDI, consequently forcing the attached phenazines out-of-plane. The title compounds showed solvent polarity-dependent fluorescence, which is indicative of intramolecular charge transfer. In conjunction with our theoretical study, the current system can be viewed as an extension of donor-acceptor-donor systems. Thermal properties characterized by differential scanning calorimetry revealed that reversible phase transitions were only observed for BTD-P. In addition, BTD-P was found to be an efficient gelator in 1,1,1-trichloroethane and toluene. The other compounds in this study did not form gels in any of the solvents tested, which may have been a result of the alkyl groups on the pendants hampering the fibrillation process.

Dataset Information

Acceptor dependent catalytic properties of GH57 4-α-glucanotransferase from Pyrococcus sp. ST04.

Publications

Acceptor dependent catalytic properties of GH57 4-α-glucanotransferase from <i>Pyrococcus</i> sp. ST04.

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