Complete nucleotide sequence of recD, the structural gene for the alpha subunit of Exonuclease V of Escherichia coli.

Intracellular amplification of the Escherichia coli RecB and RecC proteins does not result in an increase in Exonuclease V activity unless the level of a third protein, encoded between the recB and argA genes, is also amplified. Nucleotide sequence analysis of this region reveals a 1,824 nucleotide open reading frame which would encode a protein of 608 amino acids with a calculated molecular weight of 66,973. This is assumed to be the structural gene for the alpha subunit of Exonuclease V, recently designated recD. The proposed initiation codon of the recD gene overlaps the termination codon of the upstream recB gene by one nucleotide, suggesting that these genes may form an operon. The deduced amino acid sequence of the RecD protein contains a region which is homologous to highly conserved sequences in adenine nucleotide binding proteins.