Staunton D E, Thorley-Lawson D A
Department of Pathology, Tufts University School of Medicine, Boston, MA 02111.
EMBO J. 1987 Dec 1;6(12):3695-701. doi: 10.1002/j.1460-2075.1987.tb02703.x.
Blast-1 is an early activation-associated glycoprotein expressed on the surface of human lymphocytes. Here we report the isolation and analysis of a cDNA encoding Blast-1. The translated sequence of the Blast-1 cDNA contains a hydrophobic putative signal peptide and a hydrophobic carboxyl terminus devoid of charged residues. The sequence also contains five N-linked glycosylation sites, the utilization of which was confirmed by the shift in relative mol. wt of Blast-1 upon digestion with N-glycosidase F. The translated sequence reveals that Blast-1 is related to members of the immunoglobulin superfamily, especially to CD4 and MHC class II molecules. The homology to these proteins is greatest in their amino termini where they demonstrate 30-32% identity. This region of Blast-1 also demonstrated 25% identity to a V kappa sequence. Considering conservative amino acid substitutions this homology to CD4, MHC class II and V kappa becomes 60, 49 and 48%, respectively.
Blast-1是一种在人淋巴细胞表面表达的早期激活相关糖蛋白。在此我们报告编码Blast-1的cDNA的分离与分析。Blast-1 cDNA的翻译序列包含一个疏水的推定信号肽和一个没有带电残基的疏水羧基末端。该序列还包含五个N-连接糖基化位点，用N-糖苷酶F消化后Blast-1相对分子量的变化证实了这些位点的利用情况。翻译后的序列表明Blast-1与免疫球蛋白超家族成员有关，尤其是与CD4和MHC II类分子有关。与这些蛋白质在其氨基末端的同源性最高，在那里它们显示出30-32%的同一性。Blast-1的这一区域与Vκ序列也显示出25%的同一性。考虑到保守的氨基酸替换，与CD4、MHC II类和Vκ的这种同源性分别变为60%、49%和48%。
