Identification and characterization of a C‐terminally extended form of recombinant murine IL‐6

FEBS Letters

Strick, Christine A.³  James, Larry C.³  Fuller, Gerald M.²  Grenett, Hernan E.²  Otterness, Ivan G.¹  Lanzetti, Anthony J.³  Danley, Dennis E.³ 

[1] Immunology Central Research Division, Pfizer Inc., Groton, CT 06340 USA;Department of Cell Biology, University of Alabama, Birmingham, AL, USA;Departments of Molecular Genetics, Groton, CT 06340 USA

关键词: Recombinant mIL-6;    C-terminal extension;    Bioactivity;   

DOI  :  10.1016/0014-5793(91)80571-J

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Murine interleukin-6 (mIL-6) was expressed in Escherichia coli in the insoluble fraction of cell lysates. Approximately equal amounts of two polypeptide species, reactive with anti-IL-6 antibodies, were produced. The two forms of mIL-6 were isolated and found to have identical N-terminal sequences initiated by Met-Phe-Pro-Thr-Ser-Gin-. Peptide mapping after endoproteinase glu-C digestion led to isolation led to isolation and characterization of the C-terminal peptides from each of the two forms and allowed the source of the heterogeneity to be identified as a C-terminal addition of three amino acids, Gin-Lys-Leu, to authentic mIL-6. Inspection of the nucleotide sequence of the plasmid containing the mIL-6 gene and expression of the plasmid in other strains suggested that the addition of three amino acids was caused by a readthrough of the termination codon arising from an unexpected suppressor mutation in the original host strain. Although the C-terminus of IL-6 is critical for the activity of this cytokine, the IL-6 variant with extended C-terminus was fully active in two separate bioassays. This suggests that the additional amino acids do not disrupt the structure or function of this important region of the molecule.

【 授权许可】

Unknown