Amino acid sequence and post-translational modification of human interleukin 2.

Abstract

Human interleukin 2 was separated into multiple molecular forms by selective immunoaffinity chromatography and chromatofocusing. For the most part, this heterogeneity was attributed to variations in glycosylation of the threonine residue in position 3 of the polypeptide chain. The various molecular forms of interleukin 2 had nearly identical specific activities in the in vitro proliferation assay, indicating that the glycosylation had no significant effect on this response. The entire primary sequence of interleukin 2, including the location of the intramolecular disulfide bridge, was determined by a combination of peptide mapping and protein sequencing. This information should aid in the determination of the active site(s) of the molecule.

Characterization of recombinant glycosylated human interleukin 2 produced by a recombinant plasmid transformed CHO cell line

“…Sequence analysis of the purified material established that the first ten N-terminal residues of the molecule (table 1) are in agreement with the sequence previously reported for the natural product [27]. Alanine is the only residue detected at the amino-terminus, thus showing that pre-IL-2 has been efficiently cleaved at the correct position during secretion.…”

Small-Molecule Inhibitors of IL-2/IL-2R: Lessons Learned and Applied

“…IL-2, the first interleukin peptide hormone discovered, is characterized by its ability to stimulate T-cell proliferation (Nowell 1960;Morgan et al 1976;Smith 1980;Gillis et al 1982;Greene et al 1984;Robb et al 1984a). Mature IL-2, a secreted glycoprotein of 133 amino acids (15.5 kDa), is a single chain polypeptide produced by T cells in response to immune stimuli mediated by the T-cell receptor (TCR) and major histocompatibility complexes (MHC) I and II (Nelson and Willerford 1998;Malek 2008).…”

Structures of the major carbohydrates of natural human interleukin‐2

“…Carboxymethylation with radioactively labelled CH2COOH (of pre-reduced protein in 7 M guanidine hydrochloride) resulted in a significantly lower incorporation of label into IL-2 M protein compared to IL-2 N , suggesting that partial oxidation of cysteine-SH had occurred in the former component during the isolation procedure which may account for the lower specific activity of such preparations as mentioned above. It should be emphasized that the natural human interleukin-2 from lymphocytes of healthy individuals differs in its post-translational modification from the recently reported modification of the factor from the leukemic cell line Jurkat [27] in that: (a) natural lymphocyte-derived IL-2 does not contain a terminal GalNAc, a form which constitutes about 60% of the total Jurkat IL-2, and (b) the glycosylated natural IL-2 molecules contain larger-sized oligosaccharides compared to the Jurkat IL-2, where a minor form, modified by a NeuAcGalGalNAc and comprising less than 5% of the total IL-2 protein, has been reported 1271.…”