1b90
BACILLUS CEREUS BETA-AMYLASE APO FORM
| |||||||
| , resolution 2.5Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , , | ||||||
| Activity: | Beta-amylase, with EC number 3.2.1.2 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
OverviewOverview
The crystals of beta-amylase from Bacillus cereus belong to space group P21 with the following cell dimensions: a = 57.70 A, b = 92.87 A, c = 65.93 A, and beta =101.95 degrees. The structures of free and maltose-bound beta-amylases were determined by X-ray crystallography at 2.1 and 2.5 A with R-factors of 0.170 and 0.164, respectively. The final model of the maltose-bound form comprises 516 amino acid residues, four maltose molecules, 275 water molecules, one Ca2+, one acetate, and one sulfate ion. The enzyme consists of a core (beta/alpha)8-barrel domain (residues 5-434) and a C-terminal starch-binding domain (residues 435-613). Besides the active site in the core where two maltose molecules are bound in tandem, two novel maltose-binding sites were found in the core L4 region and in the C-terminal domain. The structure of the core domain is similar to that of soybean beta-amylase except for the L4 maltose-binding site, whereas the C-terminal domain has the same secondary structure as domain E of cyclodextrin glucosyltransferase. These two maltose-binding sites are 32-36 A apart from the active site. These results indicate that the ability of B. cereus beta-amylase to digest raw starch can be attributed to the additional two maltose-binding sites.
About this StructureAbout this Structure
1B90 is a Single protein structure of sequence from Bacillus cereus. Full crystallographic information is available from OCA.
ReferenceReference
Structure of raw starch-digesting Bacillus cereus beta-amylase complexed with maltose., Mikami B, Adachi M, Kage T, Sarikaya E, Nanmori T, Shinke R, Utsumi S, Biochemistry. 1999 Jun 1;38(22):7050-61. PMID:10353816
Page seeded by OCA on Sun Mar 30 18:56:05 2008