These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Crystal structures of beta-amylase from Bacillus cereus var mycoides in complexes with substrate analogs and affinity-labeling reagents.
    Author: Oyama T, Miyake H, Kusunoki M, Nitta Y.
    Journal: J Biochem; 2003 Apr; 133(4):467-74. PubMed ID: 12761294.
    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.
    [Abstract] [Full Text] [Related] [New Search]