Disulfide structures of human interleukin-6 are similar to those of human granulocyte colony stimulating factor.
The amino acid sequences of human interleukin-6 and granulocyte colony stimulating factor are approximately 30% homologous in the N-terminal region. The relative positions of four half-cystines in human interleukin-6 (IL-6) match four of the five in human granulocyte colony stimulating factor. Labeling experiments of recombinant interleukin-6 with tritiated iodoacetate confirmed that the molecule forms two intramolecular disulfide bonds and contains no detectable level of free sulfhydryls. By isolation and characterization of tryptic and subtilytic peptides obtained from different proteolytic digestions, the disulfide bonds of the IL-6 molecule were assigned to Cys44-Cys50 and Cys73-Cys83. The two disulfide bridges form two small loops which are separated by 22 amino acids. These structures are similar to those of recombinant granulocyte colony stimulating factor.
Clogston
C L
CL
Amgen Inc, Thousand Oaks, California 91320.
Boone
T C
TC
Crandall
B C
BC
Mendiaz
E A
EA
Lu
H S
HS
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003115:Colony-Stimulating Factors; D003553:Cystine; D004220:Disulfides; D004591:Electrophoresis, Polyacrylamide Gel; D016179:Granulocyte Colony-Stimulating Factor; D006098:Granulocytes; D006801:Humans; D015850:Interleukin-6; D007378:Interleukins; D008969:Molecular Sequence Data; D010446:Peptide Fragments; D011994:Recombinant Proteins; D012689:Sequence Homology, Nucleic Acid; D013381:Subtilisins; D014357:Trypsin
D000596:Amino Acids; D003115:Colony-Stimulating Factors; D004220:Disulfides; D015850:Interleukin-6; D007378:Interleukins; D010446:Peptide Fragments; D011994:Recombinant Proteins; D016179:Granulocyte Colony-Stimulating Factor; D003553:Cystine; D013381:Subtilisins; D014357:Trypsin