1SK9: Crystallographic Snapshots Of Aspergillus Fumigatus Phytase Revealing Its Enzymatic Dynamics

Understanding of the atomic movements involved in an enzymatic reaction needs structural information on the active and inactive native enzyme molecules and on the enzyme-substrate, enzyme-intermediate, and enzyme-product(s) complexes. By using the X-ray crystallographic method, four crystal structures of Aspergillus fumigatus phytase were obtained at resolution higher than 1.7 A. The pH-dependent catalytic activity of A. fumigatus phytase was linked to three water molecules that may prevent the substrate from binding and thus block nucleophilic attack of the catalytic imidazole nitrogen. Comparison of various structures also identified the water molecule that attacks the phosphamide bond during the hydrolysis process, and established the hydrolysis pathway of the intermediate. Additionally, two reaction product phosphates were observed at the active site, suggesting a possible product release pathway after hydrolysis of the intermediate. These results can help explain the catalytic mechanism throughout the whole acid phosphatase family, as all key residues are conserved.
PDB ID: 1SK9Download
MMDB ID: 29366
PDB Deposition Date: 2004/3/4
Updated in MMDB: 2012/11
Experimental Method:
x-ray diffraction
Resolution: 1.64  Å
Source Organism:
Similar Structures:
Biological Unit for 1SK9: monomeric; determined by author
Molecular Components in 1SK9
Label Count Molecule
Protein (1 molecule)
3-phytase a(Gene symbol: AFUA_4G08630)
Molecule annotation
Chemicals (5 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB