Escherichia coli (strain K12)

About this proteome

Extracted from UniProtKB

Escherichia coli is a Gram-negative straight rod, which either uses peritrichous flagella for mobility or is nonmotile. It is a facultatively anaerobic chemoorganotroph capable of both respiratory and fermentative metabolism. E.coli serves a useful function in the body by suppressing the growth of harmful bacterial species and by synthesising appreciable amounts of vitamins. It is an important component of the biosphere. It colonizes the lower gut of animals and survives when released to the natural environment, allowing widespread dissemination to new hosts. Pathogenic E.coli strains are responsible for infection of the enteric, urinary, pulmonary and nervous systems. Comparison of 20 E.coli/Shigella strains shows the core genome to be about 2000 genes while the pan-genome has over 18,000 genes. There are multiple, striking integration hotspots that are conserved across the genomes, corresponding to regions of abundant and parallel insertions and deletions of genetic material. As of 2006, highly accurate sequences are available for K-12 / MG1655 and K-12 / W3110, strains that have been separate since the mid 1950s. Sequencing of PCR products indicates that there are only eight true insertion/deletion or base differences between the two strains, in addition to 13 sites where differences are due to insertion sequences, defective prophages and two sites due to the W3110 inversion between the ribosomal RNA genes rrnD and rrnE. The K-12 strains belong to phylogenetic group A. Historically UniProtKB/Swiss-Prot considered the F plasmid to be part of the genetic makeup of strain K-12 / MG1655, whereas in fact the F plasmid was lost in a precursor strain following UV treatment and passage over blood agar. Thus we have removed the F plasmid from this genome. It can however be retrieved by searching in UniProtKB with the accession number AP001918.