Amino acids of conserved kinase motifs of cytomegalovirus protein UL97 areessential for autophosphorylation

Thirteen point mutations targeting predicted domains conserved in homologou s protein kinases were introduced into the UL97 coding region of the human cytomegalovirus. All mutagenized proteins were expressed in cells infected with recombinant vaccinia viruses (rVV). Several mutations drastically redu ced ganciclovir (GCV) phosphorylation. Mutations at amino acids G340, A442, L446, and F523 resulted in a complete loss of pUL97 phosphorylation, which mas strictly associated with a loss of GCV phosphorylation, Our results co nfirm that in rVV-infected cells pUL97 phosphorylation is due to autophosph orylation and shown that several amino acids conserved within domains of pr otein kinases are essential for this pUL97 phosphorylation, GCV phosphoryla tion is dependent on pUL97 phosphorylation.