The Deoxycytidine Pathway for Thymidylate Synthesis in Escherichia coli

When thymidylate production is diminished by a mutation affecting dCTP deaminase, Escherichia coli is known to use an alternate pathway involving deoxycytidine as an intermediate. The pathway requires the gene for any of three nucleoside diphosphate kinases ( ndk , pykA , or pykF ) and the gene for a 5′-nucleotidase ( yfbR ).