RECEPTOR AND ANTIBODY EPITOPES IN HUMAN GROWTH-HORMONE IDENTIFIED BY HOMOLOG-SCANNING MUTAGENESIS
RECEPTOR AND ANTIBODY EPITOPES IN HUMAN GROWTH-HORMONE IDENTIFIED BY HOMOLOG-SCANNING MUTAGENESIS
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DOI：
10.1126/science.2466339
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发表时间：
1989-03-10
期刊：
影响因子：
56.9
通讯作者：
WELLS, JA
中科院分区：
文献类型：
--
作者：
CUNNINGHAM, BC;JHURANI, P;WELLS, JA
本文采用同源扫描诱变的方法，对人生长激素（hGH）的肝受体和8种单克隆抗体的结合表位进行了筛选。将已知不与hGH受体或Mab结合的同源激素衍生的序列片段（7 - 30个残基长）在整个hGH基因中进行系统取代，以产生一组17种嵌合激素。每种单克隆抗体或受体通过破坏结合的突变激素的特定子集进行分类。破坏性突变的每个子集在hGh的三维模型上紧密接近地映射，即使每个子集内改变的残基通常在一级序列中是遥远的。作图分析正确地预测了那些能够或不能阻断受体与hGH结合的单克隆抗体，并进一步表明（沿着其他数据）这些嵌合激素的折叠与hGH的折叠相似。通过这种分析，hGH中的三个不连续的多肽决定簇，即残基54和74之间的环、螺旋4的中心部分到羧基末端，以及在较小程度上螺旋1的氨基末端区域调节与肝受体的结合。同源扫描突变技术在鉴定引起同源蛋白质功能变异的序列中具有广泛的应用。
A stratedy, termed homolog-scanning mutagenesis, was used to identify the epitopes on human growth hormone (hGH) for binding to its cloned liver receptor and eight different monoclonal antibodies (Mab''s). Segments of sequences (7 to 30 residues long) that were derived from homologous hormones known not to bind to the hGH receptor or Mab''s, were systematically substituted throughout the hGH gene to produce a set of 17 chimeric hormones. Each Mab or receptor was categorized by a particular subset of mutant hormones that disrupted binding. Each subset of the disruptive mutations mapped within close proximity on a three-dimensional model of hGh, even though the residues changed within each subset were usually distant in the primary sequence. The mapping analysis correctly predicted those Mab''s which could or could not block binding of the receptor to hGH and further suggested (along with other data) that the folding of these chimeric hormones is like that of hGH. By this analysis, three discontinuous polypeptide determinants in hGH.sbd.the loop between residues 54 and 74, the central portion of helix 4 to the carboxyl terminus, and to a lesser extent the amino-terminal region of helix 1.sbd.modulate binding to the liver receptor. Homolog-scanning mutagenesis should be of genera use in identifying sequences that cause functional variation among homologous proteins.