Refined structure for the complex of D-gluco-dihydroacarbose with glucoamylase from Aspergillus awamori var. X100 to 2.2 A resolution: dual conformations for extended inhibitors bound to the active site of glucoamylase.
FEBS Lett
; 358(1): 57-61, 1995 Jan 16.
Article
en En
| MEDLINE
| ID: mdl-7821430
The crystal structure at pH 4 of the complex of glucoamylase II(471) from Aspergillus awamori var. X100 with the pseudotetrasaccharide D-gluco-dihydroacarbose has been refined to an R-factor of 0.125 against data to 2.2 A resolution. The first two residues of the inhibitor bind at a position nearly identical to those of the closely related inhibitor acarbose in its complex with glucoamylase at pH 6. However, the electron density bifurcates beyond the second residue of the D-gluco-dihydroacarbose molecule, placing the third and fourth residues together at two positions in the active site. The position of relatively low density (estimated occupancy of 35%) corresponds to the location of the third and fourth residues of acarbose in its complex with glucoamylase at pH 6. The position of high density (65% occupancy) corresponds to a new binding mode of an extended inhibitor to the active site of glucoamylase. Presented are possible causes for the binding of D-gluco-dihydroacarbose in two conformations at the active site of glucoamylase at pH 4.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Conformación Proteica
/
Aspergillus
/
Trisacáridos
/
Glucano 1,4-alfa-Glucosidasa
Tipo de estudio:
Prognostic_studies
Idioma:
En
Revista:
FEBS Lett
Año:
1995
Tipo del documento:
Article
País de afiliación:
Dinamarca
Pais de publicación:
Reino Unido