1cnz
From Proteopedia
(New page: 200px<br /><applet load="1cnz" size="450" color="white" frame="true" align="right" spinBox="true" caption="1cnz, resolution 1.76Å" /> '''3-ISOPROPYLMALATE DE...) |
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| - | [[Image:1cnz.gif|left|200px]]<br /><applet load="1cnz" size=" | + | [[Image:1cnz.gif|left|200px]]<br /><applet load="1cnz" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1cnz, resolution 1.76Å" /> | caption="1cnz, resolution 1.76Å" /> | ||
'''3-ISOPROPYLMALATE DEHYDROGENASE (IPMDH) FROM SALMONELLA TYPHIMURIUM'''<br /> | '''3-ISOPROPYLMALATE DEHYDROGENASE (IPMDH) FROM SALMONELLA TYPHIMURIUM'''<br /> | ||
==Overview== | ==Overview== | ||
| - | The basis of protein stability has been investigated by the structural | + | The basis of protein stability has been investigated by the structural comparison of themophilic enzymes with their mesophilic counterparts. A number of characteristics have been found that can contribute to the stabilization of thermophilic proteins, but no one is uniquely capable of imparting thermostability. The crystal structure of 3-isopropylmalate dehydrogenase (IPMDH) from the mesophiles Escherichia coli and Salmonella typhimurium have been determined by the method of molecular replacement using the known structure of the homologous Thermus thermophilus enzyme. The structure of the E. coli enzyme was refined at a resolution of 2.1 A to an R-factor of 17.3%, that of the S. typhimurium enzyme at 1.7 A resolution to an R-factor of 19.8%. The three structures were compared to elucidate the basis of the higher thermostability of the T. thermophilus enzyme. A mutant that created a cavity in the hydrophobic core of the thermophilic enzyme was designed to investigate the importance of packing density for thermostability. The structure of this mutant was analyzed. The main stabilizing features in the thermophilic enzyme are an increased number of salt bridges, additional hydrogen bonds, a proportionately larger and more hydrophobic subunit interface, shortened N and C termini and a larger number of proline residues. The mutation in the hydrophobic core of T. thermophilus IPMDH resulted in a cavity of 32 A3, but no significant effect on the activity and thermostability of the mutant was observed. |
==About this Structure== | ==About this Structure== | ||
| - | 1CNZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium] with MN and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http:// | + | 1CNZ is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Salmonella_typhimurium Salmonella typhimurium] with <scene name='pdbligand=MN:'>MN</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1CNZ OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Single protein]] | [[Category: Single protein]] | ||
[[Category: Kryger, G.]] | [[Category: Kryger, G.]] | ||
| - | [[Category: Lovett, S | + | [[Category: Lovett, S T.]] |
[[Category: Oshima, T.]] | [[Category: Oshima, T.]] | ||
| - | [[Category: Petsko, G | + | [[Category: Petsko, G A.]] |
[[Category: Ringe, D.]] | [[Category: Ringe, D.]] | ||
[[Category: Wallon, G.]] | [[Category: Wallon, G.]] | ||
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[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:07:56 2008'' |
Revision as of 10:08, 21 February 2008
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3-ISOPROPYLMALATE DEHYDROGENASE (IPMDH) FROM SALMONELLA TYPHIMURIUM
Overview
The basis of protein stability has been investigated by the structural comparison of themophilic enzymes with their mesophilic counterparts. A number of characteristics have been found that can contribute to the stabilization of thermophilic proteins, but no one is uniquely capable of imparting thermostability. The crystal structure of 3-isopropylmalate dehydrogenase (IPMDH) from the mesophiles Escherichia coli and Salmonella typhimurium have been determined by the method of molecular replacement using the known structure of the homologous Thermus thermophilus enzyme. The structure of the E. coli enzyme was refined at a resolution of 2.1 A to an R-factor of 17.3%, that of the S. typhimurium enzyme at 1.7 A resolution to an R-factor of 19.8%. The three structures were compared to elucidate the basis of the higher thermostability of the T. thermophilus enzyme. A mutant that created a cavity in the hydrophobic core of the thermophilic enzyme was designed to investigate the importance of packing density for thermostability. The structure of this mutant was analyzed. The main stabilizing features in the thermophilic enzyme are an increased number of salt bridges, additional hydrogen bonds, a proportionately larger and more hydrophobic subunit interface, shortened N and C termini and a larger number of proline residues. The mutation in the hydrophobic core of T. thermophilus IPMDH resulted in a cavity of 32 A3, but no significant effect on the activity and thermostability of the mutant was observed.
About this Structure
1CNZ is a Single protein structure of sequence from Salmonella typhimurium with and as ligands. Full crystallographic information is available from OCA.
Reference
Crystal structures of Escherichia coli and Salmonella typhimurium 3-isopropylmalate dehydrogenase and comparison with their thermophilic counterpart from Thermus thermophilus., Wallon G, Kryger G, Lovett ST, Oshima T, Ringe D, Petsko GA, J Mol Biol. 1997 Mar 14;266(5):1016-31. PMID:9086278
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