1ob0: Difference between revisions
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[[Image:1ob0.gif|left|200px]]<br /><applet load="1ob0" size=" | [[Image:1ob0.gif|left|200px]]<br /><applet load="1ob0" size="350" color="white" frame="true" align="right" spinBox="true" | ||
caption="1ob0, resolution 1.83Å" /> | caption="1ob0, resolution 1.83Å" /> | ||
'''KINETIC STABILIZATION OF BACILLUS LICHENIFORMIS-AMYLASE THROUGH INTRODUCTION OF HYDROPHOBIC RESIDUES AT THE SURFACE'''<br /> | '''KINETIC STABILIZATION OF BACILLUS LICHENIFORMIS-AMYLASE THROUGH INTRODUCTION OF HYDROPHOBIC RESIDUES AT THE SURFACE'''<br /> | ||
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==About this Structure== | ==About this Structure== | ||
1OB0 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_licheniformis Bacillus licheniformis] with CA and NA as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] Known structural/functional Site: <scene name='pdbsite=AC1:Na Binding Site For Chain A'>AC1</scene>. Full crystallographic information is available from [http:// | 1OB0 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_licheniformis Bacillus licheniformis] with <scene name='pdbligand=CA:'>CA</scene> and <scene name='pdbligand=NA:'>NA</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alpha-amylase Alpha-amylase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.1 3.2.1.1] Known structural/functional Site: <scene name='pdbsite=AC1:Na+Binding+Site+For+Chain+A'>AC1</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1OB0 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: thermostability]] | [[Category: thermostability]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb 3 09:55:44 2008'' | ||
Revision as of 10:55, 3 February 2008
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KINETIC STABILIZATION OF BACILLUS LICHENIFORMIS-AMYLASE THROUGH INTRODUCTION OF HYDROPHOBIC RESIDUES AT THE SURFACE
OverviewOverview
It is generally assumed that in proteins hydrophobic residues are not, favorable at solvent-exposed sites, and that amino acid substitutions on, the surface have little effect on protein thermostability. Contrary to, these assumptions, we have identified hyperthermostable variants of, Bacillus licheniformis alpha-amylase (BLA) that result from the, incorporation of hydrophobic residues at the surface. Under highly, destabilizing conditions, a variant combining five stabilizing mutations, unfolds 32 times more slowly and at a temperature 13 degrees C higher than, the wild-type. Crystal structure analysis at 1.7 A resolution suggests, that stabilization is achieved through (a) extension of the concept of, increased hydrophobic packing, usually applied to cavities, to surface, indentations, (b) introduction of favorable aromatic-aromatic interactions, on the surface, (c) specific stabilization of intrinsic metal binding, sites, and (d) stabilization of a beta-sheet by introducing a residue with, high beta-sheet forming propensity. All mutated residues are involved in, forming complex, cooperative interaction networks that extend from the, interior of the protein to its surface and which may therefore constitute, "weak points" where BLA unfolding is initiated. This might explain the, unexpectedly large effect induced by some of the substitutions on the, kinetic stability of BLA. Our study shows that substantial protein, stabilization can be achieved by stabilizing surface positions that, participate in underlying cooperatively formed substructures. At such, positions, even the apparently thermodynamically unfavorable introduction, of hydrophobic residues should be explored.
About this StructureAbout this Structure
1OB0 is a Single protein structure of sequence from Bacillus licheniformis with and as ligands. Active as Alpha-amylase, with EC number 3.2.1.1 Known structural/functional Site: . Full crystallographic information is available from OCA.
ReferenceReference
Kinetic stabilization of Bacillus licheniformis alpha-amylase through introduction of hydrophobic residues at the surface., Machius M, Declerck N, Huber R, Wiegand G, J Biol Chem. 2003 Mar 28;278(13):11546-53. Epub 2003 Jan 21. PMID:12540849
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