1shn
From Proteopedia
(New page: 200px<br /><applet load="1shn" size="450" color="white" frame="true" align="right" spinBox="true" caption="1shn, resolution 2.15Å" /> '''Crystal structure of...) |
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| - | [[Image:1shn.gif|left|200px]]<br /><applet load="1shn" size=" | + | [[Image:1shn.gif|left|200px]]<br /><applet load="1shn" size="350" color="white" frame="true" align="right" spinBox="true" |
caption="1shn, resolution 2.15Å" /> | caption="1shn, resolution 2.15Å" /> | ||
'''Crystal structure of shrimp alkaline phosphatase with phosphate bound'''<br /> | '''Crystal structure of shrimp alkaline phosphatase with phosphate bound'''<br /> | ||
==Overview== | ==Overview== | ||
| - | Alkaline phosphatases (APs) are homodimeric metalloenzymes that catalyze | + | Alkaline phosphatases (APs) are homodimeric metalloenzymes that catalyze the hydrolysis and transphosphorylation of phosphate monoesters. Each monomer contains a metal-binding triad that for optimal activity is usually occupied by two zinc ions and one magnesium ion. The recently determined crystal structure of cold-active shrimp alkaline phosphatase (SAP) was, however, fully occupied by zinc ions. This paper describes a metal-exchange experiment in which the zinc ion in one binding site (referred to as the M3 site) is replaced by magnesium. Crystal structures revealed a concomitant structural change: the metal exchange causes movement of a ligating histidine into a conformation in which it does not coordinate to the metal ion. The M3 site is relevant to catalysis: its occupation by magnesium is postulated to favour catalysis and it has been suggested to be a regulatory site for other APs. Further crystallographic studies show that ligand binding can induce a conformational change of an active-site arginine from a 'non-docked' (non-interacting) to a 'docked' conformation (interacting with the ligand). The first conformation has only been observed in SAP, while the latter is common in available AP structures. The observation that the arginine does not always bind the substrate may explain the increased catalytic efficiency that is generally observed for cold-active enzymes. |
==About this Structure== | ==About this Structure== | ||
| - | 1SHN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pandalus_borealis Pandalus borealis] with NAG, ZN, PO4 and SO4 as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alkaline_phosphatase Alkaline phosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.1 3.1.3.1] Full crystallographic information is available from [http:// | + | 1SHN is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Pandalus_borealis Pandalus borealis] with <scene name='pdbligand=NAG:'>NAG</scene>, <scene name='pdbligand=ZN:'>ZN</scene>, <scene name='pdbligand=PO4:'>PO4</scene> and <scene name='pdbligand=SO4:'>SO4</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/Alkaline_phosphatase Alkaline phosphatase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=3.1.3.1 3.1.3.1] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1SHN OCA]. |
==Reference== | ==Reference== | ||
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[[Category: Pandalus borealis]] | [[Category: Pandalus borealis]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Backer, M | + | [[Category: Backer, M M.E de.]] |
[[Category: Hough, E.]] | [[Category: Hough, E.]] | ||
| - | [[Category: Lindley, P | + | [[Category: Lindley, P F.]] |
[[Category: McSweeney, S.]] | [[Category: McSweeney, S.]] | ||
[[Category: NAG]] | [[Category: NAG]] | ||
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[[Category: zinc triad]] | [[Category: zinc triad]] | ||
| - | ''Page seeded by [http:// | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 15:01:34 2008'' |
Revision as of 13:01, 21 February 2008
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Crystal structure of shrimp alkaline phosphatase with phosphate bound
Overview
Alkaline phosphatases (APs) are homodimeric metalloenzymes that catalyze the hydrolysis and transphosphorylation of phosphate monoesters. Each monomer contains a metal-binding triad that for optimal activity is usually occupied by two zinc ions and one magnesium ion. The recently determined crystal structure of cold-active shrimp alkaline phosphatase (SAP) was, however, fully occupied by zinc ions. This paper describes a metal-exchange experiment in which the zinc ion in one binding site (referred to as the M3 site) is replaced by magnesium. Crystal structures revealed a concomitant structural change: the metal exchange causes movement of a ligating histidine into a conformation in which it does not coordinate to the metal ion. The M3 site is relevant to catalysis: its occupation by magnesium is postulated to favour catalysis and it has been suggested to be a regulatory site for other APs. Further crystallographic studies show that ligand binding can induce a conformational change of an active-site arginine from a 'non-docked' (non-interacting) to a 'docked' conformation (interacting with the ligand). The first conformation has only been observed in SAP, while the latter is common in available AP structures. The observation that the arginine does not always bind the substrate may explain the increased catalytic efficiency that is generally observed for cold-active enzymes.
About this Structure
1SHN is a Single protein structure of sequence from Pandalus borealis with , , and as ligands. Active as Alkaline phosphatase, with EC number 3.1.3.1 Full crystallographic information is available from OCA.
Reference
Ligand-binding and metal-exchange crystallographic studies on shrimp alkaline phosphatase., de Backer MM, McSweeney S, Lindley PF, Hough E, Acta Crystallogr D Biol Crystallogr. 2004 Sep;60(Pt 9):1555-61. Epub 2004, Aug 26. PMID:15333925
Page seeded by OCA on Thu Feb 21 15:01:34 2008
Categories: Alkaline phosphatase | Pandalus borealis | Single protein | Backer, M M.E de. | Hough, E. | Lindley, P F. | McSweeney, S. | NAG | PO4 | SO4 | ZN | Beta sheet | Cold-active | Hydrolase | Metal triad | Phosphate | Phosphomonoester | Shrimp | Zinc | Zinc triad
