1rla
From Proteopedia
(New page: 200px<br /><applet load="1rla" size="450" color="white" frame="true" align="right" spinBox="true" caption="1rla, resolution 2.1Å" /> '''THREE-DIMENSIONAL STR...) |
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| - | [[Image:1rla.gif|left|200px]]<br /><applet load="1rla" size=" | + | [[Image:1rla.gif|left|200px]]<br /><applet load="1rla" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1rla, resolution 2.1Å" /> | caption="1rla, resolution 2.1Å" /> | ||
'''THREE-DIMENSIONAL STRUCTURE OF RAT LIVER ARGINASE, THE BINUCLEAR MANGANESE METALLOENZYME OF THE UREA CYCLE'''<br /> | '''THREE-DIMENSIONAL STRUCTURE OF RAT LIVER ARGINASE, THE BINUCLEAR MANGANESE METALLOENZYME OF THE UREA CYCLE'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Each individual excretes roughly 10 kg of urea per year, as a result of | + | Each individual excretes roughly 10 kg of urea per year, as a result of the hydrolysis of arginine in the final cytosolic step of the urea cycle. This reaction allows the disposal of nitrogenous waste from protein catabolism, and is catalysed by the liver arginase enzyme. In other tissues that lack a complete urea cycle, arginase regulates cellular arginine and ornithine concentrations for biosynthetic reactions, including nitric oxide synthesis: in the macrophage, arginase activity is reciprocally coordinated with that of NO synthase to modulate NO-dependent cytotoxicity. The bioinorganic chemistry of arginase is particularly rich because this enzyme is one of very few that specifically requires a spin-coupled Mn2+-Mn2+ cluster for catalytic activity in vitro and in vivo. The 2.1 angstrom-resolution crystal structure of trimeric rat liver arginase reveals that this unique metal cluster resides at the bottom of an active-site cleft that is 15 angstroms deep. Analysis of the structure indicates that arginine hydrolysis is achieved by a metal-activated solvent molecule which symmetrically bridges the two Mn2+ ions. |
==About this Structure== | ==About this Structure== | ||
| - | 1RLA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with MN as [http://en.wikipedia.org/wiki/ligand ligand]. 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:// | + | 1RLA is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Rattus_norvegicus Rattus norvegicus] with <scene name='pdbligand=MN:'>MN</scene> as [http://en.wikipedia.org/wiki/ligand ligand]. 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=1RLA OCA]. |
==Reference== | ==Reference== | ||
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[[Category: urea cycle]] | [[Category: urea cycle]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 14:52:08 2008'' |
Revision as of 12:52, 21 February 2008
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THREE-DIMENSIONAL STRUCTURE OF RAT LIVER ARGINASE, THE BINUCLEAR MANGANESE METALLOENZYME OF THE UREA CYCLE
Overview
Each individual excretes roughly 10 kg of urea per year, as a result of the hydrolysis of arginine in the final cytosolic step of the urea cycle. This reaction allows the disposal of nitrogenous waste from protein catabolism, and is catalysed by the liver arginase enzyme. In other tissues that lack a complete urea cycle, arginase regulates cellular arginine and ornithine concentrations for biosynthetic reactions, including nitric oxide synthesis: in the macrophage, arginase activity is reciprocally coordinated with that of NO synthase to modulate NO-dependent cytotoxicity. The bioinorganic chemistry of arginase is particularly rich because this enzyme is one of very few that specifically requires a spin-coupled Mn2+-Mn2+ cluster for catalytic activity in vitro and in vivo. The 2.1 angstrom-resolution crystal structure of trimeric rat liver arginase reveals that this unique metal cluster resides at the bottom of an active-site cleft that is 15 angstroms deep. Analysis of the structure indicates that arginine hydrolysis is achieved by a metal-activated solvent molecule which symmetrically bridges the two Mn2+ ions.
About this Structure
1RLA is a Single protein structure of sequence from Rattus norvegicus with as ligand. Active as Arginase, with EC number 3.5.3.1 Full crystallographic information is available from OCA.
Reference
Structure of a unique binuclear manganese cluster in arginase., Kanyo ZF, Scolnick LR, Ash DE, Christianson DW, Nature. 1996 Oct 10;383(6600):554-7. PMID:8849731
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