1bx4
From Proteopedia
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==Overview== | ==Overview== | ||
| - | Adenosine kinase (AK) is a key enzyme in the regulation of extracellular | + | Adenosine kinase (AK) is a key enzyme in the regulation of extracellular adenosine and intracellular adenylate levels. Inhibitors of adenosine kinase elevate adenosine to levels that activate nearby adenosine receptors and produce a wide variety of therapeutically beneficial activities. Accordingly, AK is a promising target for new analgesic, neuroprotective, and cardioprotective agents. We determined the structure of human adenosine kinase by X-ray crystallography using MAD phasing techniques and refined the structure to 1.5 A resolution. The enzyme structure consisted of one large alpha/beta domain with nine beta-strands, eight alpha-helices, and one small alpha/beta-domain with five beta-strands and two alpha-helices. The active site is formed along the edge of the beta-sheet in the large domain while the small domain acts as a lid to cover the upper face of the active site. The overall structure is similar to the recently reported structure of ribokinase from Escherichia coli [Sigrell et al. (1998) Structure 6, 183-193]. The structure of ribokinase was determined at 1.8 A resolution and represents the first structure of a new family of carbohydrate kinases. Two molecules of adenosine were present in the AK crystal structure with one adenosine molecule located in a site that matches the ribose site in ribokinase and probably represents the substrate-binding site. The second adenosine site overlaps the ADP site in ribokinase and probably represents the ATP site. A Mg2+ ion binding site is observed in a trough between the two adenosine sites. The structure of the active site is consistent with the observed substrate specificity. The active-site model suggests that Asp300 is an important catalytic residue involved in the deprotonation of the 5'-hydroxyl during the phosphate transfer. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Homo sapiens]] | [[Category: Homo sapiens]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Ealick, S | + | [[Category: Ealick, S E.]] |
| - | [[Category: Erion, M | + | [[Category: Erion, M D.]] |
| - | [[Category: Mathews, I | + | [[Category: Mathews, I I.]] |
[[Category: ADN]] | [[Category: ADN]] | ||
[[Category: CL]] | [[Category: CL]] | ||
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[[Category: human adenosine kinase]] | [[Category: human adenosine kinase]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 12:00:00 2008'' |
Revision as of 10:00, 21 February 2008
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STRUCTURE OF HUMAN ADENOSINE KINASE AT 1.50 ANGSTROMS
Overview
Adenosine kinase (AK) is a key enzyme in the regulation of extracellular adenosine and intracellular adenylate levels. Inhibitors of adenosine kinase elevate adenosine to levels that activate nearby adenosine receptors and produce a wide variety of therapeutically beneficial activities. Accordingly, AK is a promising target for new analgesic, neuroprotective, and cardioprotective agents. We determined the structure of human adenosine kinase by X-ray crystallography using MAD phasing techniques and refined the structure to 1.5 A resolution. The enzyme structure consisted of one large alpha/beta domain with nine beta-strands, eight alpha-helices, and one small alpha/beta-domain with five beta-strands and two alpha-helices. The active site is formed along the edge of the beta-sheet in the large domain while the small domain acts as a lid to cover the upper face of the active site. The overall structure is similar to the recently reported structure of ribokinase from Escherichia coli [Sigrell et al. (1998) Structure 6, 183-193]. The structure of ribokinase was determined at 1.8 A resolution and represents the first structure of a new family of carbohydrate kinases. Two molecules of adenosine were present in the AK crystal structure with one adenosine molecule located in a site that matches the ribose site in ribokinase and probably represents the substrate-binding site. The second adenosine site overlaps the ADP site in ribokinase and probably represents the ATP site. A Mg2+ ion binding site is observed in a trough between the two adenosine sites. The structure of the active site is consistent with the observed substrate specificity. The active-site model suggests that Asp300 is an important catalytic residue involved in the deprotonation of the 5'-hydroxyl during the phosphate transfer.
About this Structure
1BX4 is a Single protein structure of sequence from Homo sapiens with , and as ligands. Active as Adenosine kinase, with EC number 2.7.1.20 Known structural/functional Sites: and . Full crystallographic information is available from OCA.
Reference
Structure of human adenosine kinase at 1.5 A resolution., Mathews II, Erion MD, Ealick SE, Biochemistry. 1998 Nov 10;37(45):15607-20. PMID:9843365
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