Cloning of the Escherichia coli K-12 guaC gene following its transposition into the RP4::Mu cointegrate.

The guanosine 5'-monophosphate reductase gene, guaC, has been cloned into the multicopy vector pBR325 from the RP4::Mu cointegrate, pKGM62-1, and the gene product identified by in vitro transcription/translation as a protein of Mr 36 000. Strains harbouring the recombinant plasmid had increased levels of GMP-reductase activity.