1ud3
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Crystal structure of AmyK38 N289H mutant
OverviewOverview
The crystal structure of a calcium-free alpha-amylase (AmyK38) from, Bacillus sp. strain KSM-K38, which resists chelating reagents and chemical, oxidants, has been determined by the molecular replacement method and, refined to a crystallographic R-factor of 19.9% (R-free of 23.2%) at, 2.13-A resolution. The main chain folding of AmyK38 is almost homologous, to that of Bacillus licheniformis alpha-amylase. However, neither a highly, conserved calcium ion, which is located at the interface between domains A, and B, nor any other calcium ions appear to exist in the AmyK38 molecule, although three sodium ions were found, one of which is located at the, position corresponding to that of a highly conserved calcium ion of other, alpha-amylases. The existence of these sodium ions was, crystallographically confirmed by the structures of three metal-exchanged, and mutated enzymes. This is the first case in which the structure of the, calcium-free alpha-amylase has been determined by crystallography, and it, was suggested that these sodium ions, instead of calcium ions, are used to, retain the structure and function of AmyK38.
About this StructureAbout this Structure
1UD3 is a Single protein structure of sequence from Bacillus sp. ksm-k38 with NA as ligand. Active as Alpha-amylase, with EC number 3.2.1.1 Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of calcium-free alpha-amylase from Bacillus sp. strain KSM-K38 (AmyK38) and its sodium ion binding sites., Nonaka T, Fujihashi M, Kita A, Hagihara H, Ozaki K, Ito S, Miki K, J Biol Chem. 2003 Jul 4;278(27):24818-24. Epub 2003 Apr 28. PMID:12719434
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