Tryptophan introduction can change ß-glucan binding ability of the carbohydrate-binding module of endo-1,3-ß-glucanase.
Biosci Biotechnol Biochem
; 81(5): 951-957, 2017 May.
Article
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| MEDLINE
| ID: mdl-28388361
ABSTRACT
Endo-1,3-ß-glucanase from Cellulosimicrobium cellulans DK-1 has a carbohydrate-binding module (CBM-DK) at the C-terminal side of a catalytic domain. Out of the imperfect tandem α-, ß-, and γ-repeats in CBM-DK, the α-repeat primarily contributes to ß-glucan binding. This unique feature is derived from Trp273 in α-repeat, whose corresponding residues in ß- and γ-repeats are Asp314 and Gly358, respectively. In this study, we generated Trp-switched mutants, W273A/D314W, D270A/W273A/D314W, W273A/G358W, and D270A/W273A/G358W, and analyzed their binding abilities toward laminarioligosaccharides and laminarin. While the binding affinities of D270A/W273A and W273A mutants were either lost or much lower than that of the wild-type, those of Trp-switched mutants recovered, indicating that a Trp introduction in ß- or γ-repeat can substitute the α-repeat by primarily contributing to ß-glucan binding. Thus, we have successfully engineered a CBM-DK that binds to laminarin by a mechanism different from that of the wild-type, but with similar affinity.
Palabras clave
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Triptófano
/
Sustitución de Aminoácidos
/
Beta-Glucanos
/
Glucano Endo-1,3-beta-D-Glucosidasa
Idioma:
En
Revista:
Biosci Biotechnol Biochem
Asunto de la revista:
BIOQUIMICA
/
BIOTECNOLOGIA
Año:
2017
Tipo del documento:
Article
País de afiliación:
Japón