Part:BBa_K404110

Thyminidine kinase (mutant SR39)

General Informations

Thymidine kinase (TK) (EC 2.7.1.21) is known to be involved in the salvage pathway of nucleosides to nucleotides (Andrei et al. 2005). Due to its broader spectrum for different substrates, herpes simplex virus thymidine kinase (HSV-TK) is widely used in gene therapy approaches instead of endogenous thymidine kinases (Black et al. 1996). The transgenic introduced HSV-TK monophosphrylates nucleosides or nucleoside analogs such as ganciclovir (GCV) or acyclovir (AVC) followed by further phosphorylation through cellular kinases to nucleoside triphsphosphates. Incorporation of nucleotide analogs such as ganciclovir triphosphate or acyclovir triphosphates leads to DNA chain termination (Reardon 1989) and finally results in cell death. Genetic modifications of the active site represented by a tripeptide motif in thymidine kinase increases the substrate affinity of HSV-TK towards GCV and ACV (Black et al. 1996). Two promising mutant HSV-TKs have been found by large mutagenesis screenings modifying several amino acids and conducting sensitivity assays for ganciclovir and acyclovir (Black et al. 2001).

SR39

In contrast to the TK30 mutant, the modified thymidine kinase SR39 obtained from a semi-random (SR) mutagenesis screening contains five modifications listed in Table 1 and provides further specificity for nucleoside analogs ganciclovir and acyclovir.

Sequence and Features

Assembly Compatibility:

• 10
  COMPATIBLE WITH RFC[10]
• 12
  COMPATIBLE WITH RFC[12]
• 21
  COMPATIBLE WITH RFC[21]
• 23
  COMPATIBLE WITH RFC[23]
• 25
  INCOMPATIBLE WITH RFC[25]

  Illegal NgoMIV site found at 68
  Illegal NgoMIV site found at 973
  
• 1000
  COMPATIBLE WITH RFC[1000]

References

Andrei G, Balzarini J, Fiten P "Characterization of herpes simplex virus type 1 thymidine kinase mutants selected under a single round of high-dose brivudin." Journal of virology. 2005;79(9):5863-9.
Black ME, Newcomb TG, Wilson HM, Loeb La. "Creation of drug-specific herpes simplex virus type 1 thymidine kinase mutants for gene therapy." Proceedings of the National Academy of Sciences of the United States of America. 1996;93(8):3525-9
Black ME, Kokoris MS, Sabo P. "Herpes simplex virus-1 thymidine kinase mutants created by semi-random sequence mutagenesis improve prodrug-mediated tumor cell killing." Cancer research. 2001;61(7):3022-6
Ardiani a, Sanchez-Bonilla M, Black ME " Fusion enzymes containing HSV-1 thymidine kinase mutants and guanylate kinase enhance prodrug sensitivity in vitro and in vivo." Cancer gene therapy. 2010;17(2):86-96