Yaneva M, Wen J, Ayala A, Cook R
Department of Pharmacology, Baylor College of Medicine, Houston, Texas 77030.
J Biol Chem. 1989 Aug 15;264(23):13407-11.
The Ku antigen is a DNA-associated nuclear protein recognized by sera from patients with autoimmune diseases. It consists of two polypeptides of 86 and 70 kDa. cDNA clones encoding the 86-kDa subunit of the Ku antigen were isolated by probing lambda gt11 recombinant cDNA expression libraries with a monoclonal antibody specific for this protein. The amino acid sequence deduced from the cDNA comprises 732 amino acids and corresponds to a protein with molecular weight of 81.914. Nineteen residues at the NH2 terminus determined by protein sequencing corresponded to the sequence deduced from the cDNA. The predicted amino acid sequence contains a region with repeating leucine residues similar to the "leucine zipper" structure observed in the c-myc, v-myc, and c-fos oncogene products. The largest cDNA hybridized to 2.7- and 3.4-kilobase poly(A)+ mRNAs from HeLa cells. The cDNA clones expressed fusion proteins immunoreactive with the monoclonal antibody and sera from patients with autoimmune diseases.
Ku抗原是一种与DNA相关的核蛋白，可被自身免疫性疾病患者的血清识别。它由86 kDa和70 kDa的两种多肽组成。通过用针对该蛋白的单克隆抗体探测λgt11重组cDNA表达文库，分离出了编码Ku抗原86 kDa亚基的cDNA克隆。从cDNA推导的氨基酸序列包含732个氨基酸，对应于一个分子量为81.914的蛋白质。通过蛋白质测序确定的NH2末端的19个残基与从cDNA推导的序列一致。预测的氨基酸序列包含一个具有重复亮氨酸残基的区域，类似于在c-myc、v-myc和c-fos癌基因产物中观察到的“亮氨酸拉链”结构。最大的cDNA与来自HeLa细胞的2.7和3.4千碱基的聚腺苷酸加尾mRNA杂交。这些cDNA克隆表达的融合蛋白与单克隆抗体以及自身免疫性疾病患者的血清具有免疫反应性。
