title: C-terminal extension of truncated recombinant proteins in Escherichia coli with a 10Sa RNA decapeptide.
abstract: When murine interleukin-6 is overexpressed in Escherichia coli, a small population of molecules exhibits a novel C-terminal modification. Peptide mapping, electrospray ionization-mass spectrometry, and automated N- and C-terminal sequencing identified a peptide ("tag" peptide), -Ala-Ala-Asn-Asp-Glu-Asn-Tyr-Ala-Leu-Ala-Ala-COOH, encoded by a small metabolically stable RNA of E. coli (10Sa RNA) attached to truncated C termini of the recombinant protein. A mutant strain of E. coli in which the chromosomal 10Sa RNA gene (ssrA) is disrupted does not produce this C-terminal modification, confirming that the tag peptide originates from the ssrA gene.
authors.affiliation: Joint Protein Structure Laboratory, Ludwig Institute for Cancer Research (Melbourne Branch), Parkville, Victoria, Australia.
authors.forename: G F
authors.initials: GF
authors.lastname: Tu
authors.forename: G E
authors.initials: GE
authors.lastname: Reid
authors.forename: J G
authors.initials: JG
authors.lastname: Zhang
authors.forename: R L
authors.initials: RL
authors.lastname: Moritz
authors.forename: R J
authors.initials: RJ
authors.lastname: Simpson
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004926:Escherichia coli / Q000235:genetics*; D015850:Interleukin-6 / Q000096:biosynthesis*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000096:biosynthesis*; D012329:RNA, Bacterial / Q000235:genetics*; D011994:Recombinant Proteins / Q000096:biosynthesis*
chemical_list: D015850:Interleukin-6; D009842:Oligopeptides; D012329:RNA, Bacterial; D011994:Recombinant Proteins