CONSTRAINING B-TURN STRUCTURE IN MODEL IMMUNOGENS

免疫球蛋白分子已成为研究和生产中有价值的试剂， 诊断实验室，并已作为临床试剂在 疾病的治疗。 针对线性表位的单克隆抗体 在球状蛋白分子中有时可以通过免疫 具有源自天然蛋白质的线性肽序列。 当这些 它们通常具有低滴度，因此不具有 在研究实验室或临床中的巨大效用。 这是特别 当这种方法应用于免疫球蛋白分子时， 超家族 在产生抗肽抗体方面的有限成功 对衍生该序列的折叠蛋白质的高亲和力 可能是因为线性肽构象不类似于 折叠蛋白质中的结构。 提出了两种限制线性表位构象的方法 免疫原模型 出现在母体表面的序列 β-转角构象的蛋白质将被引入环状结构中， 肽结构，其应促进β-转角构象。 这些 序列也将取代葡萄球菌的β-转角区域， 在基因水平上使用核酸酶以产生杂合蛋白免疫原。 的 由模型引起的多克隆和单克隆抗体的亲和力 免疫原，对于亲本蛋白质将与抗体进行比较， 与类似的线性肽进行比较。 环肽的构象 杂交蛋白质将通过核磁共振光谱和X射线 晶体电泳，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.