Structure of human adenosine kinase at 1.5 A resolution

Biochemistry. 1998 Nov 10;37(45):15607-20. doi: 10.1021/bi9815445.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adenosine / metabolism
  • Adenosine Kinase / chemistry*
  • Adenosine Kinase / isolation & purification*
  • Adenosine Kinase / metabolism
  • Amino Acid Sequence
  • Binding Sites
  • Computer Simulation
  • Crystallization
  • Crystallography, X-Ray
  • Humans
  • Magnesium / metabolism
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Binding
  • Protein Structure, Secondary
  • Protein Structure, Tertiary


  • Adenosine Kinase
  • Magnesium
  • Adenosine

Associated data

  • PDB/1BX4