Site-specific mutagenesis of the human interleukin-2 gene: structure-function analysis of the cysteine residues.
The gene encoding human interleukin-2 (IL-2) has been cloned from human spleen cells, peripheral blood lymphocytes, and the Jurkat cell line. Nucleotide sequence analysis of the gene revealed that the encoded IL-2 protein has three cysteines located at amino acid residues 58, 105, and 125 of the mature protein. Site-specific mutagenesis procedures were used to modify the IL-2 gene by changing each of the cysteine codons individually to serine codons. Substitution of serine for cysteine residues at either position 58 or 105 of the IL-2 protein substantially reduced biological activity, indicating that the cysteines at these positions are necessary for maintenance of the biologically active conformation and may therefore be linked by a disulfide bridge. The modified IL-2 protein containing a substitution at position 125 retained full biological activity, suggesting that the cysteine at this position is not involved in a disulfide bond and that a free sulfhydryl group at that position is not necessary for receptor binding.
D000595:Amino Acid Sequence; D001483:Base Sequence; D002460:Cell Line; D003545:Cysteine / Q000378:metabolism; D004274:DNA, Recombinant / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics; D005796:Genes; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics*; D009154:Mutation; D011971:Receptors, Immunologic / Q000378:metabolism; D015375:Receptors, Interleukin-2; D012694:Serine / Q000378:metabolism; D013329:Structure-Activity Relationship
D004274:DNA, Recombinant; D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D012694:Serine; D003545:Cysteine