Molecular cloning of ϕ80 adsorption-inhibiting cor gene

It was reported that ϕ80 lysogens did not adsorb superinfecting phage ϕ80 and a gene responsible to the phenomenon was named cor (Kozyrev et al., 1982). We found that E. coli containing ϕ80 genome in lytic cycle also began to show resistance to superinfecting ϕ80 after 5 min of infection. We cloned the cor gene and determined its nucleotide sequence. A putative cor gene product should be 92 amino acids long and have three hydrophobic cores and one hydrophilic region, indicating a possibility of membrane binding protein. The product may interact with ϕ80 receptor on inner- or outer-membrane of E. coli cells and inhibit the adsorption of superinfecting ϕ80. The cor gene is supposed to be transcribed from a unique promoter located close to the gene.