A gene at 59 minutes on the Escherichia coli chromosome encodes a lipoprotein with unusual amino acid repeat sequences

Abstract

We report a 1.432-kb DNA sequence at 59 min on the Escherichia coli chromosome that connects the published sequences of the pcm gene for the isoaspartyl protein methyltransferase and that of the katF or rpoS (katFirpoS) gene We are interested in the widely distributed L-isoaspartyl protein methyltransferase that can modify altered aspartyl residues arising from spontaneous chemical degradation of proteins (3, 6). The methylation reaction can initiate steps leading to the restoration of the normal L-configuration of such residues and may participate as such in a protein repair step (12,22,32). The pcm gene for this enzyme had been cloned, sequenced, and mapped to the 59-min region on the chromosome of Escherichia coli (11). It is about 1 kb upstream of the katF (or rpoS) (katFirpoS) gene whose product shows strong homology to the E. coli rpoD cr70 protein (34) and appears to be a sigma factor in the central regulation of stationary-phase gene expression (28,37,43). It is interesting that pcm mutant cells demonstrate two of the phenotypes of katF/rpoS mutant cells: reduced stationary-phase survival and lessened heatshock resistance (28,29,36). Genes with similar functions can be adjacent on the E. coli chromosome, even if they are not present in one operon. For example, four operons containing genes for chemotaxis and mobility are adjacent at 41.5 min; similarly, three operons containing genes for ribosomal proteins are adjacent at about 72.4 to 73.4 min on the E. coli chromosome (1). We were thus interested in exploring whether a polypeptide or polypeptides with a function potentially similar to that of pcm or katFirpoS might be encoded in the region between these genes.In this work, we have determined and analyzed the DNA

The Salmonella typhimurium katF (rpoS) gene: cloning, nucleotide sequence, and regulation of spvR and spvABCD virulence plasmid genes

“…Thus, this protein was henceforth referred to as S. typhimurium as. In E. coli, a gene encoding a lipoprotein precursor (nlpD) was recently identified upstream of katF (14). In the S. typhimurium katF upstream region, the 3' end of an open reading frame encoding a product 100% identical to the E. coli NlpD carboxy-terminal part was detected (Fig.…”

“…A high degree of conservation of the katF gene was then confirmed at the nucleotide sequence level between the coding regions of katF in S. typhimurium, E. coli, and S. flexneri. In addition, we have shown that katF is located downstream of the nlpD gene in S. typhimurium, as is the case in E. coli (14).…”

The amoebae plate test implicates a paralogue of lpxB in the interaction of Legionella pneumophila with Acanthamoeba castellanii

“…NlpD that probably functions in cell wall formation and maintenance of Gram-negative bacteria (Ichikawa et al, 1994;Lange & Hengge-Aronis, 1994). In E. coli as well as in L. pneumophila, the nlpD gene is located immediately upstream of the rpoS gene encoding the stationary growth phase transcription factor RpoS (Hales & Shuman, 1999).…”

Growth-phase-dependent transcriptional regulation of the pcm and surE genes required for stationary-phase survival of Escherichia coli

“…Another gene, surE, that is also involved in the stationary-phase survival of E. coli is directly upstream of pcm (Li et al, 1994). Survival of Gramnegative bacteria in stationary-phase or nutrient-limited cultures that more closely resemble the conditions in the natural habitats of these organisms has been intensively studied (Kolter et al, 1993;Matin et al, 1989;Roszak & Colwell, 1987 (Ichikawa et al, 1994) and this region appears to be important for stationary-phase survival.…”