UNDERSTANDING AND REDEFNING NEUREGULIN SPECIFICITY

人神经调节蛋白与ErbB-3的高亲和力结合 受体将被用来分析受体与配体的相互作用 这一家族的EGF受体(ErbB-1)相关受体是 与各种形式的人类癌症有关。我将使用组合 计算序列分析、定向突变和噬菌体 显示选择以构建基于配基的功能图- 感受器接口。此分析将产生两个库，每个库 它代表了两个推定的 神经调节蛋白与其受体之间的接触面。这些图书馆 将单独和组合用于噬菌体展示 神经调节蛋白异构体的筛选及其与细胞的特异性结合 ErbB-2受体与ErbB-3高度同源。到目前为止，还没有 与ErbB-2特异性结合的天然配体已经完全被 特色化的。这种受体在许多细胞上过度表达 侵袭性乳腺癌细胞系。选定的ErbB-2特异性配体 可作为瞄准ErbB-2的“魔力子弹”的打靶工具 过度表达乳腺癌细胞。精选ErbB-2的有用性 神经胶蛋白的特定异构体将通过融合进行展示 利用白喉毒素的催化和易位结构域， 产生一种ErbB-2特异性定向毒素。六十个氨基酸的表皮生长因子 就像神经调节蛋白异构体的结构域一样，这将是 作为诱变的起点，也会被结晶 用于结构测定。这一结构将补充 EGF和EGF中相应结构域的现有核磁共振结构 中性调节蛋白HRG-α及其在配体受体分析中的辅助作用 互动。

The highly affinity binding of human neuregulin to the ErbB-3 receptor will be used to analyze the receptor ligand interaction in this family of EGF receptor (ErbB-1) related receptors which is implicated in various forms of human cancer. I will use a combination of computational sequence analysis, directed mutagenesis and phage display selection to construct a function based map of the ligand- receptor interface. This analysis will result in two libraries, each of which represents ten randomized residues on one of the two putative contact surfaces between neuregulin and its receptor. These libraries will be used separately and in combination for the phage display selection of neuregulin isoforms which show specific binding to the ErbB-2 receptor that is highly homologous to ErbB-3. So far, no natural ligand that binds specifically to ErbB-2 has been fully characterized. This receptor is overexpressed on a number of aggressive breast cancer cell lines. Selected ErbB-2-specific ligands can serve as targeting vehicles for "magic bullets" aimed at ErbB-2 overexpressing breast cancer cells. The usefulness of selected ErbB-2 specific isoforms of neurogulin will be demonstrated through fusion with the catalytic and translocation domains of diphtheria toxin, to generate an ErbB-2 specific directed toxin. The sixty amino acid EGF like domain of the neuregulin isoform heregulin beta, that will be used as the starting point for mutagenesis, will also be crystallized for structure determination. This structure will complement the existing NMR structures of the corresponding domain in EGF and neuregulin hrg-alpha as well as aid in the analysis of ligand receptor interaction.