We report the nucleotide sequence of the four min region of the Escherichia coli genetic map that includes the genes for ribosomal protein S2 (rpsB) and translation elongation factor EF-Ts (tsf), and the possible location of regulatory sites within this two gene operon. The data indicate that the gene order is: rpsBp-rpsB-tsf-tsft. One potential regulatory site is a 16 nucleotide sequence in the rpsB leader region encompassing the ribosome binding site and the translation initiation codon. This has a high degree of homology with nucleotides 8 through 23 on the 5' end of 165 ribosomal RNA, and might signify a sequence that is necessary for post-transcriptional control of rpsB expression. The data allow one to infer the amino acid sequences of S2 and EF-Ts.