Lee S, Zambas E D, Marsh W L, Redman C M
Lindsley F. Kimball Research Institute of the New York Blood Center, NY 10021.
Proc Natl Acad Sci U S A. 1991 Jul 15;88(14):6353-7. doi: 10.1073/pnas.88.14.6353.
The Kell blood group is a major antigenic system in human erythrocytes. Kell antigens reside on a 93-kDa membrane glycoprotein that is surface-exposed and associated with the underlying cytoskeleton. We isolated tryptic peptides and, based on the amino acid sequence of one of the peptides and by using the PCR, prepared a specific oligonucleotide to screen a lambda gt10 human bone-marrow cDNA library. Four clones were isolated, one containing cDNA with an open reading frame for an 83-kDa protein. All known Kell amino acid sequences were present in the deduced sequence; moreover, rabbit antibody to a 30-amino acid peptide, prepared from this sequence, reacted on an immunoblot with authentic Kell protein. The Kell cDNA sequence predicts a 732-amino acid protein. Hydropathy analysis indicates a single membrane-spanning region, suggesting that Kell protein is oriented with 47 of its N-terminal amino acids in the cell cytoplasm, and a 665-amino acid segment, which contains six possible N-glycosylation sites, is located extracellularly. Computer-based search showed that Kell has structural and sequence homology to a family of zinc metalloglycoproteins with neutral endopeptidase activity.
凯尔血型系统是人类红细胞中的一个主要抗原系统。凯尔抗原存在于一种93 kDa的膜糖蛋白上，该蛋白暴露于表面并与下方的细胞骨架相关联。我们分离了胰蛋白酶肽段，并根据其中一个肽段的氨基酸序列，利用聚合酶链反应（PCR）制备了一种特异性寡核苷酸，用于筛选λgt10人骨髓cDNA文库。分离出了四个克隆，其中一个克隆包含一个具有83 kDa蛋白开放阅读框的cDNA。推导序列中包含所有已知的凯尔氨基酸序列；此外，用该序列制备的针对30个氨基酸肽段的兔抗体，在免疫印迹中与天然凯尔蛋白发生反应。凯尔cDNA序列预测为一种732个氨基酸的蛋白。亲水性分析表明存在一个单一的跨膜区域，这表明凯尔蛋白的N端47个氨基酸位于细胞质中，而包含六个可能的N糖基化位点的665个氨基酸片段位于细胞外。基于计算机的搜索显示，凯尔与具有中性内肽酶活性的锌金属糖蛋白家族在结构和序列上具有同源性。
