This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1bx4
From Proteopedia
|
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 CL, MG and ADN as ligands. Active as Adenosine kinase, with EC number 2.7.1.20 Structure known Active Sites: ADA and ADB. 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
Page seeded by OCA on Mon Nov 12 16:15:12 2007
