Structure of human dCK suggests strategies to improve anticancer and antiviral therapy.
Human deoxycytidine kinase (dCK) phosphorylates the natural deoxyribonucleosides deoxycytidine (dC), deoxyguanosine (dG) and deoxyadenosine (dA) and is an essential enzyme for the phosphorylation of numerous nucleoside analog prodrugs routinely used in cancer and antiviral chemotherapy. For many of these compounds, the phosphorylation step catalyzed by dCK is the rate-limiting step in their overall activation pathway. To determine the factors that limit the phosphorylation efficiency of the prodrug, we solved the crystal structure of dCK to a resolution of 1.6 A in complex with its physiological substrate deoxycytidine and with the prodrugs AraC and gemcitabine. The structures reveal the determinants of dCK substrate specificity. Especially relevant to new prodrug development is the interaction between Arg128 and the hydrogen-bond acceptor at the sugar 2'-arabinosyl position of AraC and gemcitabine. On the basis of the structures, we designed a catalytically superior dCK variant that could be used in suicide gene-therapy applications.
Sabini
Elisabetta
E
University of Illinois at Chicago, Department of Biochemistry and Molecular Biology, 1819 West Polk Street, Chicago, Illinois 60612, USA.
Ort
Stephan
S
Monnerjahn
Christian
C
Konrad
Manfred
M
Lavie
Arnon
A
D000595:Amino Acid Sequence; D000970:Antineoplastic Agents / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D000998:Antiviral Agents / Q000378:metabolism / Q000493:pharmacokinetics / Q000494:pharmacology*; D001711:Biotransformation; D003842:Deoxycytidine Kinase / Q000737:chemistry*; D006801:Humans; D008958:Models, Molecular; D008969:Molecular Sequence Data; D011487:Protein Conformation; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity
D000970:Antineoplastic Agents; D000998:Antiviral Agents; D003842:Deoxycytidine Kinase