Download MendeleyCrystal Structures of beta-Amylase from Bacillus cereus var. mycoides in Complexes with Substrate Analogs and Affinity-Labeling Reagents
Oyama, T., Miyake, H., Kusunoki, M., Nitta, Y.(2003) J Biochem 133: 467-474
- PubMed: 12761294
- DOI: https://doi.org/10.1093/jb/mvg061
- Primary Citation of Related Structures:
1J0Y, 1J0Z, 1J10, 1J11, 1J12 - PubMed 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.
Organizational Affiliation:
Laboratory of Enzyme Chemistry, Graduate School of Agriculture and Biological Science, Osaka Prefecture University, Sakai, Osaka 599-8531. nitta@biochem.osakafu-u.ac.jp
