title: Repetitive sequences in the murein-lipoprotein of the cell wall of Escherichia coli.
abstract: The amino-acid sequence of the murein-lipoprotein of the Escherichia coli cell wall is presented. This protein is covalently bound to a lipid component as well as to the murein (peptidoglycan, mucopeptide). The sequence is also highly repetitive. At the N-terminal portion, there are three adjacent almost identical sequences, indicating repeated duplication of a gene coding originally for 15 amino acids. The C-terminal part of the polypeptide chain is more variable but still shows striking homology when certain sequence gaps are introduced. The lipid is bound to the N-terminal serine of the dipeptide (Ser-Ser) that extends from the repetitive sequence. At the C-terminal end where the murein is bound, a tripeptide extends from the repetitive portion. Here there are several basic amino acids and the only aromatic amino acid in the lipoprotein. The sequence is Lys-Tyr-Arg-Lys. The linkage to the murein is formed between the epsilon-amino group of the C-terminal lysine and the carboxyl group of the optical L-center of meso-diaminopimelic acid. The polypeptide chain is composed of 57 amino acids and lacks glycine, proline, cysteine, phenylalanine, histidine, and tryptophan. 63% of the amino acids are hydrophilic, but because of the covalently linked lipid this structural membrane protein has very hydrophobic properties.
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D001665:Binding Sites; D002473:Cell Wall / Q000032:analysis*; D002854:Chromatography, Paper; D010450:Endopeptidases; D004926:Escherichia coli / Q000032:analysis*; D005815:Genetic Code; D006025:Glycosaminoglycans / Q000032:analysis*; D008074:Lipoproteins / Q000032:analysis*; D010443:Peptide Chain Termination, Translational; D010457:Peptidoglycan / Q000032:analysis; D011135:Polysaccharides, Bacterial / Q000032:analysis*; D011402:Pronase; D011485:Protein Binding; D013820:Thermolysin; D014357:Trypsin
chemical_list: D000596:Amino Acids; D006025:Glycosaminoglycans; D008074:Lipoproteins; D010457:Peptidoglycan; D011135:Polysaccharides, Bacterial; D010450:Endopeptidases; D014357:Trypsin; D011402:Pronase; D013820:Thermolysin