Molecular and biochemical characterizations of a new cold-active and mildly alkaline ß-Mannanase from Verrucomicrobiae DG1235.
Prep Biochem Biotechnol
; 51(9): 881-891, 2021.
Article
em En
| MEDLINE
| ID: mdl-33439094
ABSTRACT
Mannanases catalyze the cleavage of ß-1,4-mannosidic linkages in mannans and have various applications in different biotechnological industries. In this study, a new ß-mannanase from Verrucomicrobiae DG1235 (ManDG1235) was biochemically characterized and its enzymatic properties were revealed. Amino acid alignment indicated that ManDG1235 belonged to glycoside hydrolase family 26 and shared a low amino acid sequence identity to reported ß-mannanases (up to 50% for CjMan26C from Cellvibrio japonicus). ManDG1235 was expressed in Escherichia coli. Purified ManDG1235 (rManDG1235) exhibited the typical properties of cold-active enzymes, including high activity at low temperature (optimal at 20 °C) and thermal instability. The maximum activity of rManDG1235 was achieved at pH 8, suggesting that it is a mildly alkaline ß-mannanase. rManDG1235 was able to hydrolyze a variety of mannan substrates and was active toward certain types of glucans. A structural model that was built by homology modeling suggested that ManDG1235 had four mannose-binding subsites which were symmetrically arranged in the active-site cleft. A long loop linking ß2 and α2 as in CjMan26C creates a steric border in the glycone region of active-site cleft which probably leads to the exo-acting feature of ManDG1235, for specifically cleaving mannobiose from the non-reducing end of the substrate.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Proteínas de Bactérias
/
Modelos Moleculares
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Temperatura Baixa
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Beta-Manosidase
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Verrucomicrobia
Idioma:
En
Revista:
Prep Biochem Biotechnol
Assunto da revista:
BIOQUIMICA
/
BIOTECNOLOGIA
Ano de publicação:
2021
Tipo de documento:
Article
País de afiliação:
China