Overproduction and identification of the ftsO gene product, an essential cell division protein in Escherichia coli K-12

ftsQ is an essential cell division gene in Escherichia coli . The ftsQ gene has been sequenced, and a presumptive open reading frame has been identified; however, no protein product has been observed. The ftsQ gene was isolated on a 970-base-pair EcoRI-PvuII fragment of the E. coli chromosome and used to construct a trp-lac (P sub(tac)) transcriptional fusion in plasmid pKK223-3. The fused construct (pDSC78) complemented an ftsQl (Ts) mutant strain in trans, restoring growth at 42 degree C on low-salt medium. An ftsQl (Ts) mutant strain transformed with pDSC78 appeared normal upon microscopic examination, with no indication of filamentation. The ftsQ gene product was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and two-dimensional gel electrophoresis of radiolabeled, isopropyl- beta -D-thiogalactopyranoside-induced maxicell and normal cell extracts. As predicted from the nucleotide sequence, the 970-base-pair EcoRI-PvuII fragment encoded a polypeptide of approximately 31,400 daltons.