1b8f
From Proteopedia
(New page: 200px<br /><applet load="1b8f" size="450" color="white" frame="true" align="right" spinBox="true" caption="1b8f, resolution 2.1Å" /> '''HISTIDINE AMMONIA-LYA...) |
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| - | [[Image:1b8f.gif|left|200px]]<br /><applet load="1b8f" size=" | + | [[Image:1b8f.gif|left|200px]]<br /><applet load="1b8f" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1b8f, resolution 2.1Å" /> | caption="1b8f, resolution 2.1Å" /> | ||
'''HISTIDINE AMMONIA-LYASE (HAL) FROM PSEUDOMONAS PUTIDA'''<br /> | '''HISTIDINE AMMONIA-LYASE (HAL) FROM PSEUDOMONAS PUTIDA'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Histidine ammonia-lyase (EC 4.3.1.3) catalyzes the nonoxidative | + | Histidine ammonia-lyase (EC 4.3.1.3) catalyzes the nonoxidative elimination of the alpha-amino group of histidine and is closely related to the important plant enzyme phenylalanine ammonia-lyase. The crystal structure of histidase from Pseudomonas putida was determined at 2.1 A resolution revealing a homotetramer with D2 symmetry, the molecular center of which is formed by 20 nearly parallel alpha-helices. The chain fold, but not the sequence, resembles those of fumarase C and related proteins. The structure shows that the reactive electrophile is a 4-methylidene-imidazole-5-one, which is formed autocatalytically by cyclization and dehydration of residues 142-144 with the sequence Ala-Ser-Gly. With respect to the first dehydration step, this modification resembles the chromophore of the green fluorescent protein. The active center is clearly established by the modification and by mutations. The observed geometry allowed us to model the bound substrate at a high confidence level. A reaction mechanism is proposed. |
==About this Structure== | ==About this Structure== | ||
| - | 1B8F is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida] with SO4 and GOL as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Histidine_ammonia-lyase Histidine ammonia-lyase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.3.1.3 4.3.1.3] Full crystallographic information is available from [http:// | + | 1B8F is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pseudomonas_putida Pseudomonas putida] with <scene name='pdbligand=SO4:'>SO4</scene> and <scene name='pdbligand=GOL:'>GOL</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Histidine_ammonia-lyase Histidine ammonia-lyase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=4.3.1.3 4.3.1.3] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1B8F OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Pseudomonas putida]] | [[Category: Pseudomonas putida]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Schulz, G | + | [[Category: Schulz, G E.]] |
| - | [[Category: Schwede, T | + | [[Category: Schwede, T F.]] |
[[Category: GOL]] | [[Category: GOL]] | ||
[[Category: SO4]] | [[Category: SO4]] | ||
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[[Category: histidine degradation]] | [[Category: histidine degradation]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 11:52:35 2008'' |
Revision as of 09:52, 21 February 2008
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HISTIDINE AMMONIA-LYASE (HAL) FROM PSEUDOMONAS PUTIDA
Overview
Histidine ammonia-lyase (EC 4.3.1.3) catalyzes the nonoxidative elimination of the alpha-amino group of histidine and is closely related to the important plant enzyme phenylalanine ammonia-lyase. The crystal structure of histidase from Pseudomonas putida was determined at 2.1 A resolution revealing a homotetramer with D2 symmetry, the molecular center of which is formed by 20 nearly parallel alpha-helices. The chain fold, but not the sequence, resembles those of fumarase C and related proteins. The structure shows that the reactive electrophile is a 4-methylidene-imidazole-5-one, which is formed autocatalytically by cyclization and dehydration of residues 142-144 with the sequence Ala-Ser-Gly. With respect to the first dehydration step, this modification resembles the chromophore of the green fluorescent protein. The active center is clearly established by the modification and by mutations. The observed geometry allowed us to model the bound substrate at a high confidence level. A reaction mechanism is proposed.
About this Structure
1B8F is a Single protein structure of sequence from Pseudomonas putida with and as ligands. Active as Histidine ammonia-lyase, with EC number 4.3.1.3 Full crystallographic information is available from OCA.
Reference
Crystal structure of histidine ammonia-lyase revealing a novel polypeptide modification as the catalytic electrophile., Schwede TF, Retey J, Schulz GE, Biochemistry. 1999 Apr 27;38(17):5355-61. PMID:10220322
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