1hvx
| |||||||
| , resolution 2.0Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , | ||||||
| Gene: | AMYT631 (Geobacillus stearothermophilus) | ||||||
| Activity: | Alpha-amylase, with EC number 3.2.1.1 | ||||||
| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
BACILLUS STEAROTHERMOPHILUS ALPHA-AMYLASE
OverviewOverview
The crystal structure of a thermostable alpha-amylase from Bacillus stearothermophilus (BSTA) has been determined at 2.0 A resolution. The main-chain fold is almost identical to that of the known crystal structure of Bacillus licheniformis alpha-amylase (BLA). BLA is known to be more stable than BSTA. A structural comparison between the crystal structures of BSTA and BLA showed significant differences that may account for the difference in their thermostabilities, as follows. (i) The two-residue insertion in BSTA, Ile181-Gly182, pushes away the spatially contacting region including Asp207, which corresponds to Ca(2+)-coordinating Asp204 in BLA. As a result, Asp207 cannot coordinate the Ca(2+). (ii) BSTA contains nine fewer hydrogen bonds than BLA, which costs about 12 kcal/mol. This tendency is prominent in the (beta/alpha)(8)-barrel, where 10 fewer hydrogen bonds were observed in BSTA. BLA forms a denser hydrogen bond network in the inter-helical region, which may stabilize alpha-helices in the barrel. (iii) A few small voids observed in the alpha-helical region of the (beta/alpha)(8)-barrel in BSTA decrease inter-helical compactness and hydrophobic interactions. (iv) The solvent-accessible surface area of charged residues in BLA is about two times larger than that in BSTA.
About this StructureAbout this Structure
1HVX is a Single protein structure of sequence from Geobacillus stearothermophilus. Full crystallographic information is available from OCA.
ReferenceReference
Crystal structure of Bacillus stearothermophilus alpha-amylase: possible factors determining the thermostability., Suvd D, Fujimoto Z, Takase K, Matsumura M, Mizuno H, J Biochem. 2001 Mar;129(3):461-8. PMID:11226887
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