5cev
From Proteopedia
(New page: 200px<br /><applet load="5cev" size="450" color="white" frame="true" align="right" spinBox="true" caption="5cev, resolution 2.5Å" /> '''ARGINASE FROM BACILLU...) |
|||
| Line 1: | Line 1: | ||
| - | [[Image:5cev.gif|left|200px]]<br /><applet load="5cev" size=" | + | [[Image:5cev.gif|left|200px]]<br /><applet load="5cev" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="5cev, resolution 2.5Å" /> | caption="5cev, resolution 2.5Å" /> | ||
'''ARGINASE FROM BACILLUS CALDEVELOX, L-LYSINE COMPLEX'''<br /> | '''ARGINASE FROM BACILLUS CALDEVELOX, L-LYSINE COMPLEX'''<br /> | ||
==Overview== | ==Overview== | ||
| - | BACKGROUND: Arginase is a manganese-dependent enzyme that catalyzes the | + | BACKGROUND: Arginase is a manganese-dependent enzyme that catalyzes the hydrolysis of L-arginine to L-ornithine and urea. In ureotelic animals arginase is the final enzyme of the urea cycle, but in many species it has a wider role controlling the use of arginine for other metabolic purposes, including the production of creatine, polyamines, proline and nitric oxide. Arginase activity is regulated by various small molecules, including the product L-ornithine. The aim of these structural studies was to test aspects of the catalytic mechanism and to investigate the structural basis of arginase inhibition. RESULTS: We report here the crystal structures of arginase from Bacillus caldovelox at pH 5.6 and pH 8.5, and of binary complexes of the enzyme with L-arginine, L-ornithine and L-lysine at pH 8.5. The arginase monomer comprises a single compact alpha/beta domain that further associates into a hexameric quaternary structure. The binary complexes reveal a common mode of ligand binding, which places the substrate adjacent to the dimanganese centre. We also observe a conformational change that impacts on the active site and is coupled with the occupancy of an external site by guanidine or arginine. CONCLUSIONS: The structures reported here clarify aspects of the active site and indicate key features of the catalytic mechanism, including substrate coordination to one of the manganese ions and an orientational role for a neighboring histidine residue. Stereospecificity for L-amino acids is found to depend on their precise recognition at the active-site rim. Identification of a second arginine-binding site, remote from the active site, and associated conformational changes lead us to propose a regulatory role for this site in substrate hydrolysis. |
==About this Structure== | ==About this Structure== | ||
| - | 5CEV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_caldovelox Bacillus caldovelox] with MN, LYS and GAI as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Arginase Arginase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.3.1 3.5.3.1] Full crystallographic information is available from [http:// | + | 5CEV is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Bacillus_caldovelox Bacillus caldovelox] with <scene name='pdbligand=MN:'>MN</scene>, <scene name='pdbligand=LYS:'>LYS</scene> and <scene name='pdbligand=GAI:'>GAI</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Arginase Arginase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.5.3.1 3.5.3.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=5CEV OCA]. |
==Reference== | ==Reference== | ||
| Line 14: | Line 14: | ||
[[Category: Bacillus caldovelox]] | [[Category: Bacillus caldovelox]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Baker, E | + | [[Category: Baker, E N.]] |
| - | [[Category: Bewley, M | + | [[Category: Bewley, M C.]] |
| - | [[Category: Jeffrey, P | + | [[Category: Jeffrey, P D.]] |
| - | [[Category: Kanyo, Z | + | [[Category: Kanyo, Z F.]] |
| - | [[Category: Patchett, M | + | [[Category: Patchett, M L.]] |
[[Category: GAI]] | [[Category: GAI]] | ||
[[Category: LYS]] | [[Category: LYS]] | ||
| Line 28: | Line 28: | ||
[[Category: nitrogen metabolism]] | [[Category: nitrogen metabolism]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 19:14:56 2008'' |
Revision as of 17:14, 21 February 2008
|
ARGINASE FROM BACILLUS CALDEVELOX, L-LYSINE COMPLEX
Overview
BACKGROUND: Arginase is a manganese-dependent enzyme that catalyzes the hydrolysis of L-arginine to L-ornithine and urea. In ureotelic animals arginase is the final enzyme of the urea cycle, but in many species it has a wider role controlling the use of arginine for other metabolic purposes, including the production of creatine, polyamines, proline and nitric oxide. Arginase activity is regulated by various small molecules, including the product L-ornithine. The aim of these structural studies was to test aspects of the catalytic mechanism and to investigate the structural basis of arginase inhibition. RESULTS: We report here the crystal structures of arginase from Bacillus caldovelox at pH 5.6 and pH 8.5, and of binary complexes of the enzyme with L-arginine, L-ornithine and L-lysine at pH 8.5. The arginase monomer comprises a single compact alpha/beta domain that further associates into a hexameric quaternary structure. The binary complexes reveal a common mode of ligand binding, which places the substrate adjacent to the dimanganese centre. We also observe a conformational change that impacts on the active site and is coupled with the occupancy of an external site by guanidine or arginine. CONCLUSIONS: The structures reported here clarify aspects of the active site and indicate key features of the catalytic mechanism, including substrate coordination to one of the manganese ions and an orientational role for a neighboring histidine residue. Stereospecificity for L-amino acids is found to depend on their precise recognition at the active-site rim. Identification of a second arginine-binding site, remote from the active site, and associated conformational changes lead us to propose a regulatory role for this site in substrate hydrolysis.
About this Structure
5CEV is a Single protein structure of sequence from Bacillus caldovelox with , and as ligands. Active as Arginase, with EC number 3.5.3.1 Full crystallographic information is available from OCA.
Reference
Crystal structures of Bacillus caldovelox arginase in complex with substrate and inhibitors reveal new insights into activation, inhibition and catalysis in the arginase superfamily., Bewley MC, Jeffrey PD, Patchett ML, Kanyo ZF, Baker EN, Structure. 1999 Apr 15;7(4):435-48. PMID:10196128
Page seeded by OCA on Thu Feb 21 19:14:56 2008
