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| [[Image:1hvx.gif|left|200px]] | | {{Seed}} |
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| {{STRUCTURE_1hvx| PDB=1hvx | SCENE= }} | | {{STRUCTURE_1hvx| PDB=1hvx | SCENE= }} |
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| '''BACILLUS STEAROTHERMOPHILUS ALPHA-AMYLASE'''
| | ===BACILLUS STEAROTHERMOPHILUS ALPHA-AMYLASE=== |
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| ==Overview==
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| 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.
| | The line below this paragraph, {{ABSTRACT_PUBMED_11226887}}, adds the Publication Abstract to the page |
| | (as it appears on PubMed at http://www.pubmed.gov), where 11226887 is the PubMed ID number. |
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| | {{ABSTRACT_PUBMED_11226887}} |
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| ==About this Structure== | | ==About this Structure== |
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| [[Category: Sodium]] | | [[Category: Sodium]] |
| [[Category: Thermostability]] | | [[Category: Thermostability]] |
| ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 19:17:03 2008'' | | |
| | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Tue Jul 1 08:53:37 2008'' |