The sbcC gene product of Escherichia coli interferes with the growth of a lambda red gam phage carrying a long palindrome in its DNA. This phenotype was used to identify recombinant plasmids harbouring the wild-type gene and to isolate sbcC mutant derivatives carrying Tn1000 insertions. Analysis of these plasmids located sbcC between proC and phoR at a slightly different position from that reported before (Lloyd, R.G. and Buckman, C. 1985, J. Bacteriol. 164, 836-844). Nucleotide sequencing revealed that the gene spans a DNA segment of 3.3 kb that encodes a poorly expressed protein of 118 kDa and which lies downstream of a gene of unknown function that encodes a polypeptide of 45 kDa. The amino acid sequence of SbcC contains a nucleotide binding fold similar to that in RecB and other recombination proteins.