1leh
From Proteopedia
(New page: 200px<br /><applet load="1leh" size="450" color="white" frame="true" align="right" spinBox="true" caption="1leh, resolution 2.2Å" /> '''LEUCINE DEHYDROGENASE...) |
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| - | [[Image:1leh.gif|left|200px]]<br /><applet load="1leh" size=" | + | [[Image:1leh.gif|left|200px]]<br /><applet load="1leh" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1leh, resolution 2.2Å" /> | caption="1leh, resolution 2.2Å" /> | ||
'''LEUCINE DEHYDROGENASE FROM BACILLUS SPHAERICUS'''<br /> | '''LEUCINE DEHYDROGENASE FROM BACILLUS SPHAERICUS'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: Glutamate, phenylalanine and leucine dehydrogenases catalyze | + | BACKGROUND: Glutamate, phenylalanine and leucine dehydrogenases catalyze the NAD(P)(+)-linked oxidative deamination of L-amino acids to the corresponding 2-oxoacids, and sequence homology between these enzymes clearly indicates the existence of an enzyme superfamily related by divergent evolution. We have undertaken structural studies on a number of members of this family in order to investigate the molecular basis of their differential amino acid specificity. RESULTS: We have solved the X-ray structure of the leucine dehydrogenase from Bacillus sphaericus to a resolution of 2.2 A. Each subunit of this octameric enzyme contains 364 amino acids and folds into two domains, separated by a deep cleft. The nicotinamide ring of the NAD+ cofactor binds deep in this cleft, which is thought to close during the hydride transfer step of the catalytic cycle. CONCLUSIONS: Comparison of the structure of leucine dehydrogenase with a hexameric glutamate dehydrogenase has shown that these two enzymes share a related fold and possess a similar catalytic chemistry. A mechanism for the basis of the differential amino acid specificity between these enzymes involves point mutations in the amino acid side-chain specificity pocket and subtle changes in the shape of this pocket caused by the differences in quaternary structure. |
==About this Structure== | ==About this Structure== | ||
| - | 1LEH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Lysinibacillus_sphaericus Lysinibacillus sphaericus]. Active as [http://en.wikipedia.org/wiki/Leucine_dehydrogenase Leucine dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.4.1.9 1.4.1.9] Full crystallographic information is available from [http:// | + | 1LEH is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Lysinibacillus_sphaericus Lysinibacillus sphaericus]. Active as [http://en.wikipedia.org/wiki/Leucine_dehydrogenase Leucine dehydrogenase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=1.4.1.9 1.4.1.9] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1LEH OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Lysinibacillus sphaericus]] | [[Category: Lysinibacillus sphaericus]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Baker, P | + | [[Category: Baker, P J.]] |
| - | [[Category: Rice, D | + | [[Category: Rice, D W.]] |
| - | [[Category: Sedelnikova, S | + | [[Category: Sedelnikova, S E.]] |
| - | [[Category: Stillman, T | + | [[Category: Stillman, T J.]] |
| - | [[Category: Turnbull, A | + | [[Category: Turnbull, A P.]] |
[[Category: oxidoreductase]] | [[Category: oxidoreductase]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 13:44:18 2008'' |
Revision as of 11:44, 21 February 2008
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LEUCINE DEHYDROGENASE FROM BACILLUS SPHAERICUS
Overview
BACKGROUND: Glutamate, phenylalanine and leucine dehydrogenases catalyze the NAD(P)(+)-linked oxidative deamination of L-amino acids to the corresponding 2-oxoacids, and sequence homology between these enzymes clearly indicates the existence of an enzyme superfamily related by divergent evolution. We have undertaken structural studies on a number of members of this family in order to investigate the molecular basis of their differential amino acid specificity. RESULTS: We have solved the X-ray structure of the leucine dehydrogenase from Bacillus sphaericus to a resolution of 2.2 A. Each subunit of this octameric enzyme contains 364 amino acids and folds into two domains, separated by a deep cleft. The nicotinamide ring of the NAD+ cofactor binds deep in this cleft, which is thought to close during the hydride transfer step of the catalytic cycle. CONCLUSIONS: Comparison of the structure of leucine dehydrogenase with a hexameric glutamate dehydrogenase has shown that these two enzymes share a related fold and possess a similar catalytic chemistry. A mechanism for the basis of the differential amino acid specificity between these enzymes involves point mutations in the amino acid side-chain specificity pocket and subtle changes in the shape of this pocket caused by the differences in quaternary structure.
About this Structure
1LEH is a Single protein structure of sequence from Lysinibacillus sphaericus. Active as Leucine dehydrogenase, with EC number 1.4.1.9 Full crystallographic information is available from OCA.
Reference
A role for quaternary structure in the substrate specificity of leucine dehydrogenase., Baker PJ, Turnbull AP, Sedelnikova SE, Stillman TJ, Rice DW, Structure. 1995 Jul 15;3(7):693-705. PMID:8591046
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