5A2B: Crystal Structure Of Anoxybacillus Alpha-amylase Provides Insights Into A New Glycosyl Hydrolase Subclass

A new subfamily of glycosyl hydrolase family GH13 was recently proposed for alpha-amylases from Anoxybacillus species (ASKA and ADTA), Geobacillus thermoleovorans (GTA, Pizzo, and GtamyII), Bacillus aquimaris (BaqA), and 95 other putative protein homologues. To understand this new GH13 subfamily, we report crystal structures of truncated ASKA (TASKA). ASKA is a thermostable enzyme capable of producing high levels of maltose. Unlike GTA, biochemical analysis showed that Ca(2+) ion supplementation enhances the catalytic activities of ASKA and TASKA. The crystal structures reveal the presence of four Ca(2+) ion binding sites, with three of these binding sites are highly conserved among Anoxybacillus alpha-amylases. This work provides structural insights into this new GH13 subfamily both in the apo form and in complex with maltose. Furthermore, structural comparison of TASKA and GTA provides an overview of the conformational changes accompanying maltose binding at each subsite.
PDB ID: 5A2BDownload
MMDB ID: 137850
PDB Deposition Date: 2015/5/17
Updated in MMDB: 2016/04
Experimental Method:
x-ray diffraction
Resolution: 1.85  Å
Source Organism:
Similar Structures:
Biological Unit for 5A2B: monomeric; determined by author and by software (PISA)
Molecular Components in 5A2B
Label Count Molecule
Protein (1 molecule)
Anoxybacillus Alpha-amylase
Molecule annotation
Chemicals (5 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB