PDBsum entry 1j10

Hydrolase

PDB id: 1j10

Contents

Protein chains

516 a.a. *

Ligands

XYP-GLC-GLC ×7

XYS-GLC-GLC

Metals

_CA ×4

Waters ×562

* Residue conservation analysis

PDB id:

1j10

Name:

Hydrolase

Title:

Beta-amylase from bacillus cereus var. Mycoides in complex with ggx

Structure:

Beta-amylase. Chain: a, b, c, d. Synonym: 1,4-alpha-d-glucan maltohydrolase. Ec: 3.2.1.2

Source:

Bacillus cereus. Organism_taxid: 1396. Strain: var. Mycoides

Resolution:

2.10Å R-factor: 0.189 R-free: 0.239

Authors:

T.Oyama,H.Miyake,M.Kusunoki,Y.Nitta

Key ref:

T.Oyama et al. (2003). Crystal structures of beta-amylase from Bacillus cereus var mycoides in complexes with substrate analogs and affinity-labeling reagents. J Biochem (tokyo), 133, 467-474. PubMed id: 12761294

Date:

25-Nov-02 Release date: 17-Jun-03

Protein chains

P36924  (AMYB_BACCE) -  Beta-amylase from Bacillus cereus

Seq: 546 a.a.

Struc: 516 a.a.

Enzyme reactions

• Enzyme class: E.C.3.2.1.2 - beta-amylase.
• Reaction: Hydrolysis of 1,4-alpha-glucosidic linkages in polysaccharides so as to remove successive maltose units from the non-reducing ends of the chains.

J Biochem (tokyo) 133:467-474 (2003)

PubMed id: 12761294

Crystal structures of beta-amylase from Bacillus cereus var mycoides in complexes with substrate analogs and affinity-labeling reagents.

T.Oyama, H.Miyake, M.Kusunoki, Y.Nitta.

ABSTRACT

The crystal structures of beta-amylase from Bacillus cereus var. mycoides in complexes with five inhibitors were solved. The inhibitors used were three substrate analogs, i.e. glucose, maltose (product), and a synthesized compound, O-alpha-D-glucopyranosyl-(1-->4)-O-alpha-D-glucopyranosyl-(1-->4)-D-xylopyranose (GGX), and two affinity-labeling reagents with an epoxy alkyl group at the reducing end of glucose. For all inhibitors, one molecule was bound at the active site cleft and the non-reducing end glucose of the four inhibitors except GGX was located at subsite 1, accompanied by a large conformational change of the flexible loop (residues 93-97), which covered the bound inhibitor. In addition, another molecule of maltose or GGX was bound about 30 A away from the active site. A large movement of residues 330 and 331 around subsite 3 was also observed upon the binding of GGX at subsites 3 to 5. Two affinity-labeling reagents, alpha-EPG and alpha-EBG, were covalently bound to a catalytic residue (Glu-172). A substrate recognition mechanism for the beta-amylase was discussed based on the modes of binding of these inhibitors in the active site cleft.