Robinson E A, Yoshimura T, Leonard E J, Tanaka S, Griffin P R, Shabanowitz J, Hunt D F, Appella E
Laboratory of Cell Biology, National Cancer Institute, Bethesda, MD 20892.
Proc Natl Acad Sci U S A. 1989 Mar;86(6):1850-4. doi: 10.1073/pnas.86.6.1850.
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.
在一项关于趋化因子白细胞特异性结构基础的研究中，我们确定了人胶质瘤衍生的单核细胞趋化因子（GDCF-2）的完整氨基酸序列，该肽可吸引人类单核细胞但不吸引中性粒细胞。选择肿瘤细胞产物进行分析是因为其相对丰度以及与淋巴细胞衍生趋化因子（LDCF）无法区分的氨基酸组成，LDCF被认为是细胞免疫反应中单核细胞聚集的激动剂。通过埃德曼降解和质谱联用，确定GDCF-2由76个氨基酸残基组成，从N端的焦谷氨酸开始。该肽在第11、12、36和52位含有四个半胱氨酸，形成一对环，聚集在二硫键处。半胱氨酸的相对位置与单核细胞衍生的中性粒细胞趋化因子（MDNCF）几乎相同，MDNCF质量相似但与GDCF的序列同一性仅为24%。因此，由于聚集二硫键形成的环，GDCF和MDNCF具有相似的总体二级结构，它们不同的白细胞特异性很可能由一级序列的巨大差异决定。
