CONSTRAINING B-TURN STRUCTURE IN MODEL IMMUNOGENS

免疫球蛋白分子已成为研究和开发中有价值的试剂 诊断实验室，并已作为临床试剂在 疾病的治疗。针对线性表位的单抗 在球状蛋白质中，分子有时可以通过免疫产生 具有源自天然蛋白质的线性多肽序列。当这些 抗体被识别出来，它们通常效价低，因此不 在研究实验室或临床上有很大的实用价值。这是特别的 当这种方法应用于免疫球蛋白分子时，这是正确的。 超级大家庭。在产生抗肽抗体方面取得的成功有限 与衍生该序列的折叠蛋白的高亲和力 可能是因为线状肽的构象不像 在折叠的蛋白质中发现的结构。 提出了两种约束线性表位构象的方法 在模型免疫原中。出现在亲本表面上的序列 具有Beta转角构象的蛋白质将被引入到环状 应该促进Beta-Turn构象的多肽结构。这些 序列也将被替换为葡萄球菌的Beta转角区域 核酸酶在基因水平产生一种杂交蛋白免疫原。这个 模型诱导的多克隆抗体和单抗的亲和力 免疫原，用于母体蛋白将与产生的抗体进行比较 对相似的线状多肽的作用。环肽的构象 杂化蛋白将通过核磁共振波谱和x射线进行表征。 结晶学，以允许详细的分子解释 免疫学数据。

Immunolglobulin molecules have become valuable reagents in research and diagnostic laboratories and have been tested as clinical reagents in the treatment of disease. Monoclonal antibodies directed to a linear epitope in a globular protein molecule can sometimes be generated by immunizing with linear peptide sequences derived from the native protein. When these antibodies are identified they are generally of low titer and thus not of great utility in the research laboratory or clinic. This is particularly true when this approach has been applied to molecules of the immunoglobulin superfamily. The limited success in generating antipeptide antibodies with a high affinity for the folded protein from which the sequence was derived may arise because the linear peptide conformation does not resemble the structure found in the folded protein. Two methods are proposed to constrain the conformation of linear epitopes in model immunogens. Sequences which occur on the surface of a parent protein in a Beta-turn conformation will be introduced into a cyclic peptide structure which should promote a Beta-turn conformation. These sequences will also be substitited for a Beta-turn region of staphylococcal nuclease at the gene level to produce a hybrid protein immunogen. The affinity of polyclonal and monoclonal antibodies, elicited by the model immunogens, for the parent protein will be compared with antibodies raised against similar linear peptides. The conformation of the cyclic peptides and hybrid proteins will be characterized by NMR spectroscopy and x-ray crystallagrophy to allow a detailed molecular interpretation of the immunological data.