1d1s
From Proteopedia
(New page: 200px<br /> <applet load="1d1s" size="450" color="white" frame="true" align="right" spinBox="true" caption="1d1s, resolution 2.5Å" /> '''WILD-TYPE HUMAN SIGM...) |
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| - | [[Image:1d1s.gif|left|200px]]<br /> | + | [[Image:1d1s.gif|left|200px]]<br /><applet load="1d1s" size="350" color="white" frame="true" align="right" spinBox="true" |
| - | <applet load="1d1s" size=" | + | |
caption="1d1s, resolution 2.5Å" /> | caption="1d1s, resolution 2.5Å" /> | ||
'''WILD-TYPE HUMAN SIGMA (CLASS IV) ALCOHOL DEHYDROGENASE'''<br /> | '''WILD-TYPE HUMAN SIGMA (CLASS IV) ALCOHOL DEHYDROGENASE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Pyrazole and its 4-alkyl substituted derivatives are potent inhibitors for | + | Pyrazole and its 4-alkyl substituted derivatives are potent inhibitors for many alcohol dehydrogenases. However, the human sigma sigma isoenzyme exhibits a 580-fold lower affinity for 4-methylpyrazole than does the human beta1beta1 isoenzyme, with which it shares 69% sequence identity. In this study, structural and kinetic studies were utilized in an effort to identify key structural features that affect the binding of 4-methylpyrazole in human alcohol dehydrogenase isoenzymes. We have extended the resolution of the human sigma sigma alcohol dehydrogenase (ADH) isoenzyme to 2.5 A resolution. Comparison of this structure to the human beta1beta1 isoenzyme structure indicated that the side-chain position for Met141 in sigma sigma ADH might interfere with 4-methylpyrazole binding. Mutation of Met141 in sigma sigma ADH to Leu (sigma141L) lowers the Ki for 4-methylpyrazole from 350 to 10 microM, while having a much smaller effect on the Ki for pyrazole. Thus, the mutagenesis results show that the residue at position 141, which lines the substrate-binding pocket at a position close to the methyl group of 4-methylpyrazole, directly affects the binding of the inhibitor. To rule out nonspecific structural changes due to the mutation, the X-ray structure of the sigma141L mutant enzyme was determined to 2.4 A resolution. The three-dimensional structure of the mutant enzyme is identical to the wild-type enzyme, with the exception of the residue at position 141. Thus, the differences in 4-methylpyrazole binding between the mutant and wild-type sigma sigma ADH isoenzymes can be completely ascribed to the local changes in the topology of the substrate binding site, and provides an explanation for the class-specific differences in 4-methylpyrazole binding to the human ADH isoenzymes. |
==About this Structure== | ==About this Structure== | ||
| - | 1D1S 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 ZN, ACT, CAC and NAD as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alcohol_dehydrogenase Alcohol dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.1 1.1.1.1] Full crystallographic information is available from [http:// | + | 1D1S 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=ZN:'>ZN</scene>, <scene name='pdbligand=ACT:'>ACT</scene>, <scene name='pdbligand=CAC:'>CAC</scene> and <scene name='pdbligand=NAD:'>NAD</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alcohol_dehydrogenase Alcohol dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.1.1.1 1.1.1.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1D1S OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Hurley, T | + | [[Category: Hurley, T D.]] |
| - | [[Category: Xie, P | + | [[Category: Xie, P T.]] |
[[Category: ACT]] | [[Category: ACT]] | ||
[[Category: CAC]] | [[Category: CAC]] | ||
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[[Category: rossman or dinucleotide fold]] | [[Category: rossman or dinucleotide fold]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:12:03 2008'' |
Revision as of 10:12, 21 February 2008
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WILD-TYPE HUMAN SIGMA (CLASS IV) ALCOHOL DEHYDROGENASE
Overview
Pyrazole and its 4-alkyl substituted derivatives are potent inhibitors for many alcohol dehydrogenases. However, the human sigma sigma isoenzyme exhibits a 580-fold lower affinity for 4-methylpyrazole than does the human beta1beta1 isoenzyme, with which it shares 69% sequence identity. In this study, structural and kinetic studies were utilized in an effort to identify key structural features that affect the binding of 4-methylpyrazole in human alcohol dehydrogenase isoenzymes. We have extended the resolution of the human sigma sigma alcohol dehydrogenase (ADH) isoenzyme to 2.5 A resolution. Comparison of this structure to the human beta1beta1 isoenzyme structure indicated that the side-chain position for Met141 in sigma sigma ADH might interfere with 4-methylpyrazole binding. Mutation of Met141 in sigma sigma ADH to Leu (sigma141L) lowers the Ki for 4-methylpyrazole from 350 to 10 microM, while having a much smaller effect on the Ki for pyrazole. Thus, the mutagenesis results show that the residue at position 141, which lines the substrate-binding pocket at a position close to the methyl group of 4-methylpyrazole, directly affects the binding of the inhibitor. To rule out nonspecific structural changes due to the mutation, the X-ray structure of the sigma141L mutant enzyme was determined to 2.4 A resolution. The three-dimensional structure of the mutant enzyme is identical to the wild-type enzyme, with the exception of the residue at position 141. Thus, the differences in 4-methylpyrazole binding between the mutant and wild-type sigma sigma ADH isoenzymes can be completely ascribed to the local changes in the topology of the substrate binding site, and provides an explanation for the class-specific differences in 4-methylpyrazole binding to the human ADH isoenzymes.
About this Structure
1D1S is a Single protein structure of sequence from Homo sapiens with , , and as ligands. Active as Alcohol dehydrogenase, with EC number 1.1.1.1 Full crystallographic information is available from OCA.
Reference
Methionine-141 directly influences the binding of 4-methylpyrazole in human sigma sigma alcohol dehydrogenase., Xie PT, Hurley TD, Protein Sci. 1999 Dec;8(12):2639-44. PMID:10631979
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