This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1hvx
From Proteopedia
OCA (Talk | contribs)
(New page: 200px<br /><applet load="1hvx" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hvx, resolution 2.0Å" /> '''BACILLUS STEAROTHERMO...)
Next diff →
Revision as of 14:44, 20 November 2007
|
BACILLUS STEAROTHERMOPHILUS ALPHA-AMYLASE
Overview
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 Structure
1HVX is a Single protein structure of sequence from Geobacillus stearothermophilus with CA and NA as ligands. Active as Alpha-amylase, with EC number 3.2.1.1 Full crystallographic information is available from OCA.
Reference
Crystal structure of Bacillus stearothermophilus alpha-amylase: possible factors determining the thermostability., Suvd D, Fujimoto Z, Takase K, Matsumura M, Mizuno H, J Biochem (Tokyo). 2001 Mar;129(3):461-8. PMID:11226887
Page seeded by OCA on Tue Nov 20 16:51:37 2007
