CLONING OF THE ALPHA-CHAIN OF HUMAN-PLATELET GLYCOPROTEIN-IB - A TRANSMEMBRANE PROTEIN WITH HOMOLOGY TO LEUCINE-RICH ALPHA-2-GLYCOPROTEIN
CLONING OF THE ALPHA-CHAIN OF HUMAN-PLATELET GLYCOPROTEIN-IB - A TRANSMEMBRANE PROTEIN WITH HOMOLOGY TO LEUCINE-RICH ALPHA-2-GLYCOPROTEIN
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DOI：
10.1073/pnas.84.16.5615
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发表时间：
1987-08-01
影响因子：
11.1
通讯作者：
ROTH, GJ
中科院分区：
文献类型：
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作者：
LOPEZ, JA;CHUNG, DW;ROTH, GJ
糖蛋白 Ib 是血小板的表面膜糖蛋白，充当血管性血友病因子的受体。它是由α组成的异二聚体。和一个.beta。由二硫键连接的链。使用针对α的糖运载蛋白部分的亲和纯化的抗体筛选由来自人红白血病细胞系HEL的mRNA制备的噬菌体λgt11 cDNA表达文库。糖蛋白Ib链。分离并噬菌斑纯化十一个阳性克隆。最大的 cDNA 插入片段长度为 2420 个核苷酸，编码 16 个氨基酸的前导序列和一个终止密码子。它还含有 42 个核苷酸的 5'' 非编码序列和 497 个核苷酸的 3'' 非编码序列，包括聚 (A) 尾。 .α的氨基酸序列。从cDNA预测的GPIb链与用胰蛋白酶或金黄色葡萄球菌V8蛋白酶消化后对从人血小板糖运载蛋白中分离的肽进行Edman降解确定的156个氨基酸的序列完全一致。 .alpha的胞质外结构域。 GPIb 亚基包含几个值得注意的结构特征，包括由 24 个氨基酸组成的 7 个串联重复区域，这些氨基酸与富含亮氨酸的 α2-糖蛋白中存在的氨基酸同源。胞质外结构域还包含两个亲水区域，一个富含带电氨基酸，第二个富含丝氨酸和苏氨酸残基。富含丝氨酸和苏氨酸的区域包括九个氨基酸的五个重复以及分子中存在的大部分 O-连接碳水化合物位点。胞质外结构域之后是大约 29 个氨基酸的潜在跨膜片段和位于分子羧基末端的大约 100 个氨基酸的潜在胞内结构域。
Glycoprotein Ib is a surface membrane glycoprotein of platelets that functions as a receptor for von Willebrand factor. It is a heterodimer composed of an .alpha. and a .beta. chain linked by a disulfide bond(s). A phage .lambda.gt11 cDNA expression library prepared from mRNA from a human erythroleukemia cell line, HEL, was screened using an affinity-purified antibody to the glycocalicin portion of the .alpha. chain of glycoprotein Ib. Eleven positive clones were isolated and plaque-purified. The largest cDNA insert was 2420 nucleotides in length and coded for a leader sequence of 16 amino acids, and a stop codon. It also contained 42 nucleotides of 5''noncoding sequence and 497 nucleotides of 3'' noncoding sequence, including a poly(A) tail. The amino acid sequence of the .alpha. chain of GPIb predicted from the cDNA agreed completely with the sequence of 156 amino acids that was determined by Edman degradation of peptides isolated from human platelet glycocalicin after digestion with trypsin or Staphylococcus aureus V8 protease. The extracytoplasmic domain of the .alpha. subunit of GPIb contains several noteworthy structural features, including a region of seven tandem repeats of 24 amino acids that are homologous with those present in leucine-rich .alpha.2-glycoprotein. The extracytoplasmic domain also contains two hydrophilic regions, one rich in charged amino acids and a second rich in serine and threonine residues. The region rich in serine and threonine includes five repeats of nine amino acids as well as the majority of the O-linked carbohydrate sites present in the molecule. The extracytoplasmic domain is followed by a potential transmembrane segment of approximately 29 amino acid and a potential intracellular domain of approximately 100 amino acids located at the carboxyl end of the molecule.