1ge0: Difference between revisions
New page: left|200px<br /> <applet load="1ge0" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ge0, resolution 1.8Å" /> '''CRYSTAL STRUCTURE OF... |
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'''CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS'''<br /> | '''CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS'''<br /> | ||
==Overview== | ==Overview== | ||
To understand the role of non-Gly residues in the left-handed helical | To understand the role of non-Gly residues in the left-handed helical conformation for the conformational stability of a protein, the non-Gly to Gly and Ala mutations at six left-handed residues (R21, Y38, R50, Q58, H78, and N118) of the human lysozyme were examined. The thermodynamic parameters for denaturation were determined using a differential scanning calorimeter, and the crystal structures were analyzed by X-ray crystallography. If a left-handed non-Gly had an unfavorable steric interaction between the side-chain Cbeta and backbone, the Gly mutation would be expected to stabilize more than the Ala mutation at the same position. For the mutant human lysozymes, however, there were few differences in the denaturation Gibbs energy (DeltaG) between the Gly and Ala mutants, except for the substitution at position 58. Analysis of the changes in stability (DeltaDeltaG) based on the structures of the wild-type and mutant proteins showed that the experimental DeltaDeltaG value of Q58G was approximately 7 kJ/mol higher than the estimated value without consideration of any local steric interaction. These results indicate that only Q58G increased the stability by elimination of local constraints. The residue 58 is located at the most rigid position in the left-handed non-Gly residues and is involved in its enzymatic function. It can be concluded that the left-handed non-Gly residues do not always have unfavorable strain energies as compared with Gly at the same position. | ||
==Disease== | ==Disease== | ||
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==About this Structure== | ==About this Structure== | ||
1GE0 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with NA as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Lysozyme Lysozyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.17 3.2.1.17] Full crystallographic information is available from [http:// | 1GE0 is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=NA:'>NA</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. Active as [http://en.wikipedia.org/wiki/Lysozyme Lysozyme], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.2.1.17 3.2.1.17] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GE0 OCA]. | ||
==Reference== | ==Reference== | ||
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[[Category: stability]] | [[Category: stability]] | ||
''Page seeded by [http:// | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:49:00 2008'' | ||
Revision as of 13:49, 21 February 2008
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CRYSTAL STRUCTURE OF MUTANT HUMAN LYSOZYME SUBSTITUTED AT LEFT-HANDED HELICAL POSITIONS
OverviewOverview
To understand the role of non-Gly residues in the left-handed helical conformation for the conformational stability of a protein, the non-Gly to Gly and Ala mutations at six left-handed residues (R21, Y38, R50, Q58, H78, and N118) of the human lysozyme were examined. The thermodynamic parameters for denaturation were determined using a differential scanning calorimeter, and the crystal structures were analyzed by X-ray crystallography. If a left-handed non-Gly had an unfavorable steric interaction between the side-chain Cbeta and backbone, the Gly mutation would be expected to stabilize more than the Ala mutation at the same position. For the mutant human lysozymes, however, there were few differences in the denaturation Gibbs energy (DeltaG) between the Gly and Ala mutants, except for the substitution at position 58. Analysis of the changes in stability (DeltaDeltaG) based on the structures of the wild-type and mutant proteins showed that the experimental DeltaDeltaG value of Q58G was approximately 7 kJ/mol higher than the estimated value without consideration of any local steric interaction. These results indicate that only Q58G increased the stability by elimination of local constraints. The residue 58 is located at the most rigid position in the left-handed non-Gly residues and is involved in its enzymatic function. It can be concluded that the left-handed non-Gly residues do not always have unfavorable strain energies as compared with Gly at the same position.
DiseaseDisease
Known diseases associated with this structure: Amyloidosis, renal OMIM:[153450], Microphthalmia, syndromic 1 OMIM:[309800]
About this StructureAbout this Structure
1GE0 is a Single protein structure of sequence from Homo sapiens with as ligand. Active as Lysozyme, with EC number 3.2.1.17 Full crystallographic information is available from OCA.
ReferenceReference
Role of non-glycine residues in left-handed helical conformation for the conformational stability of human lysozyme., Takano K, Yamagata Y, Yutani K, Proteins. 2001 Aug 15;44(3):233-43. PMID:11455596
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