title: Recombinant human IL-6 expressed in E. coli undergoes selective N-terminal degradation: evidence that the protein consists of a stable core and a nonessential flexible N-terminal.
abstract: A synthetic gene for human interleukin-6 has been expressed in E. coli. The protein has been purified and renatured and has the same activity as natural human IL-6 using the 7TD1 cell proliferation assay. The protein undergoes specific cleavage by a thiol protease, yielding two new N-termini at Arg-9 and His-15. The truncated proteins retain full biological activity. The degradation results in the loss of sharp amide resonances in the 1H-NMR spectrum, and little change to the ultraviolet CD spectrum. Several amino acid type assignments could be made for these sharp amides using a DQF-COSY 2D-NMR experiment. The N-terminal 15 amino acids exist as a flexible, random coil, attached to a central structure.
authors.affiliation: Glaxo Institute for Molecular Biology S.A., Geneva, Switzerland.
authors.forename: A E
authors.initials: AE
authors.lastname: Proudfoot
authors.forename: S C
authors.initials: SC
authors.lastname: Brown
authors.forename: A R
authors.initials: AR
authors.lastname: Bernard
authors.forename: J Y
authors.initials: JY
authors.lastname: Bonnefoy
authors.forename: E H
authors.initials: EH
authors.lastname: Kawashima
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D002942:Circular Dichroism; D004926:Escherichia coli / Q000235:genetics; D005813:Genes, Synthetic; D006801:Humans; D015850:Interleukin-6 / Q000737:chemistry* / Q000235:genetics; D009682:Magnetic Resonance Spectroscopy; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry
chemical_list: D015850:Interleukin-6; D011994:Recombinant Proteins