Elucidation of human choline kinase crystal structures in complex with the products ADP or phosphocholine.
Choline kinase, responsible for the phosphorylation of choline to phosphocholine as the first step of the CDP-choline pathway for the biosynthesis of phosphatidylcholine, has been recognized as a new target for anticancer therapy. Crystal structures of human choline kinase in its apo, ADP and phosphocholine-bound complexes, respectively, reveal the molecular details of the substrate binding sites. ATP binds in a cavity where residues from both the N and C-terminal lobes contribute to form a cleft, while the choline-binding site constitutes a deep hydrophobic groove in the C-terminal domain with a rim composed of negatively charged residues. Upon binding of choline, the enzyme undergoes conformational changes independently affecting the N-terminal domain and the ATP-binding loop. From this structural analysis and comparison with other kinases, and from mutagenesis data on the homologous Caenorhabditis elegans choline kinase, a model of the ternary ADP.phosphocholine complex was built that reveals the molecular basis for the phosphoryl transfer activity of this enzyme.
Malito
Enrico
E
Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.
Sekulic
Nikolina
N
Too
Wei Cun See
WC
Konrad
Manfred
M
Lavie
Arnon
A
D000244:Adenosine Diphosphate / Q000737:chemistry*; D000255:Adenosine Triphosphate / Q000737:chemistry; D000595:Amino Acid Sequence; D001665:Binding Sites; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry; D002794:Choline / Q000737:chemistry*; D002797:Choline Kinase / Q000737:chemistry*; D018360:Crystallography, X-Ray; D006801:Humans; D057927:Hydrophobic and Hydrophilic Interactions; D008958:Models, Molecular; D008969:Molecular Sequence Data; D010767:Phosphorylcholine / Q000737:chemistry*; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D029742:Caenorhabditis elegans Proteins; D010767:Phosphorylcholine; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D002797:Choline Kinase; D002794:Choline