The association of thymidine kinase activity and thymidine transport in Escherichia coli.
We have constructed a series of mutants within the putative nucleoside-binding site of the herpes simplex type-1 virus (HSV-1) thymidine kinase (TK)-encoding gene (tk), contained within an expression vector. While most mutations within this sequence produce an inactive protein, we find no absolute requirement for the wild-type Ile166 and Ala167. The uptake of thymidine (dT) into Escherichia coli tdk-, lacking functional endogenous TK activity, is proportional to the amount of TK activity expressed from the heterologous HSV-1 tk gene. In contrast, there is no enhancement in deoxycytidine uptake into E. coli producing (HSV-1) TK. These results imply a specific role for TK in the active transport of dT into E. coli.
Dube
D K
DK
Department of Pathology, Joseph Gottstein Memorial Cancer Research Laboratory, University of Washington, Seattle 98195.
Horwitz
M S
MS
Loeb
L A
LA
D000595:Amino Acid Sequence; D001483:Base Sequence; D001692:Biological Transport; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D011994:Recombinant Proteins / Q000378:metabolism; D018139:Simplexvirus / Q000201:enzymology / Q000235:genetics*; D013936:Thymidine / Q000378:metabolism*; D013937:Thymidine Kinase / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
D011994:Recombinant Proteins; D013937:Thymidine Kinase; D013936:Thymidine