Complete amino acid sequence of a human monocyte chemoattractant, a putative mediator of cellular immune reactions.
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Robinson EA, Yoshimura T, Leonard EJ, Tanaka S, Griffin PR, Shabanowitz J, Hunt DF, Appella E
Complete amino acid sequence of a human monocyte chemoattractant, a putative mediator of cellular immune reactions.
Proc Natl Acad Sci U S A. 1989 Mar;86(6):1850-4.
- PubMed ID
- 2648385 [ View in PubMed]
- Abstract
In a study of the structural basis for leukocyte specificity of chemoattractants, we determined the complete amino acid sequence of human glioma-derived monocyte chemotactic factor (GDCF-2), a peptide that attracts human monocytes but not neutrophils. The choice of a tumor cell product for analysis was dictated by its relative abundance and an amino acid composition indistinguishable from that of lymphocyte-derived chemotactic factor (LDCF), the agonist thought to account for monocyte accumulation in cellular immune reactions. By a combination of Edman degradation and mass spectrometry, it was established that GDCF-2 comprises 76 amino acid residues, commencing at the N terminus with pyroglutamic acid. The peptide contains four half-cystines, at positions 11, 12, 36, and 52, which create a pair of loops, clustered at the disulfide bridges. The relative positions of the half-cystines are almost identical to those of monocyte-derived neutrophil chemotactic factor (MDNCF), a peptide of similar mass but with only 24% sequence identity to GDCF. Thus, GDCF and MDNCF have a similar gross secondary structure because of the loops formed by the clustered disulfides, and their different leukocyte specificities are most likely determined by the large differences in primary sequence.