1gkm
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Histidine ammonia-lyase (EC 4.3.1.3) catalyzes the nonoxidative, elimination of the alpha-amino group of histidine using a, 4-methylidene-imidazole-5-one (MIO), which is formed autocatalytically, from the internal peptide segment 142Ala-Ser-Gly. The structure of the, enzyme inhibited by a reaction with l-cysteine was established at the very, high resolution of 1.0 A. Five active center mutants were produced and, their catalytic activities were measured. Among them, mutant Tyr280-->Phe, could be crystallized and its structure could be determined at 1.7 A, resolution. It contains a planar sp2-hybridized 144-N atom of MIO, in, contrast to the pyramidal sp3-hybridized 144-N of the wild-type. With the, planar 144-N atom, MIO assumes the conformation of a putative intermediate, aromatic ... | + | Histidine ammonia-lyase (EC 4.3.1.3) catalyzes the nonoxidative, elimination of the alpha-amino group of histidine using a, 4-methylidene-imidazole-5-one (MIO), which is formed autocatalytically, from the internal peptide segment 142Ala-Ser-Gly. The structure of the, enzyme inhibited by a reaction with l-cysteine was established at the very, high resolution of 1.0 A. Five active center mutants were produced and, their catalytic activities were measured. Among them, mutant Tyr280-->Phe, could be crystallized and its structure could be determined at 1.7 A, resolution. It contains a planar sp2-hybridized 144-N atom of MIO, in, contrast to the pyramidal sp3-hybridized 144-N of the wild-type. With the, planar 144-N atom, MIO assumes the conformation of a putative intermediate, aromatic state of the reaction, demonstrating that the conformational, barrier between aromatic and wild-type states is very low. The data led to, a new proposal for the geometry for the catalyzed reaction, which also, applies to the closely related phenylalanine ammonia-lyase (EC 4.3.1.5)., Moreover, it suggested an intermediate binding site for the released, ammonia. |
==About this Structure== | ==About this Structure== | ||
| - | 1GKM is a | + | 1GKM 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, CYS, O 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] Structure known Active Site: MIO. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=1GKM OCA]. |
==Reference== | ==Reference== | ||
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[[Category: lyase]] | [[Category: lyase]] | ||
| - | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Mon Nov 5 12:30:37 2007'' |
Revision as of 10:25, 5 November 2007
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HISTIDINE AMMONIA-LYASE (HAL) FROM PSEUDOMONAS PUTIDA INHIBITED WITH L-CYSTEINE
Overview
Histidine ammonia-lyase (EC 4.3.1.3) catalyzes the nonoxidative, elimination of the alpha-amino group of histidine using a, 4-methylidene-imidazole-5-one (MIO), which is formed autocatalytically, from the internal peptide segment 142Ala-Ser-Gly. The structure of the, enzyme inhibited by a reaction with l-cysteine was established at the very, high resolution of 1.0 A. Five active center mutants were produced and, their catalytic activities were measured. Among them, mutant Tyr280-->Phe, could be crystallized and its structure could be determined at 1.7 A, resolution. It contains a planar sp2-hybridized 144-N atom of MIO, in, contrast to the pyramidal sp3-hybridized 144-N of the wild-type. With the, planar 144-N atom, MIO assumes the conformation of a putative intermediate, aromatic state of the reaction, demonstrating that the conformational, barrier between aromatic and wild-type states is very low. The data led to, a new proposal for the geometry for the catalyzed reaction, which also, applies to the closely related phenylalanine ammonia-lyase (EC 4.3.1.5)., Moreover, it suggested an intermediate binding site for the released, ammonia.
About this Structure
1GKM is a Single protein structure of sequence from Pseudomonas putida with SO4, CYS, O and GOL as ligands. Active as Histidine ammonia-lyase, with EC number 4.3.1.3 Structure known Active Site: MIO. Full crystallographic information is available from OCA.
Reference
Structures of two histidine ammonia-lyase modifications and implications for the catalytic mechanism., Baedeker M, Schulz GE, Eur J Biochem. 2002 Mar;269(6):1790-7. PMID:11895450
Page seeded by OCA on Mon Nov 5 12:30:37 2007
Categories: Histidine ammonia-lyase | Pseudomonas putida | Single protein | Baedeker, M. | Schulz, G.E. | CYS | GOL | O | SO4 | Ammonia-lyase | Histidine degradation | Lyase
