Abdullah L H, Ordronneau P, Petrusz P
Department of Cell Biology and Anatomy, University of North Carolina, Chapel Hill 27599.
Neuroscience. 1992 Dec;51(3):729-38. doi: 10.1016/0306-4522(92)90311-o.
Molecular requirements for hapten recognition by antibodies raised in rabbits against glutaraldehyde conjugates of L-glutamate and L-aspartate were determined in enzyme immunoassays by measuring the displacement of binding of glutamate and aspartate, respectively, by a large number of selected haptens to two anti-glutamate and two anti-aspartate sera. The results indicate that N-terminal modifications of the amino acids, such as the presence of an N-acetyl or N-carbamyl group or the addition of a second amino acid to form dipeptides with C-terminal glutamate or aspartate, are tolerated to variable degrees, more so by the aspartate than the glutamate antisera. The antibodies possess point-to-point recognition sites for the two carboxyl groups present in both amino acids. Strong shape complementarity between the amino acids and their respective binding sites is suggested by the lack of recognition of the appropriate D stereoisomers by any of the antibodies. Changes in the distance between the two carboxyl groups, or modification, replacement or loss of either or both carboxyl groups, strongly reduce or eliminate binding. Based on these results, we suggest that other antibodies raised to similar conjugates of these amino acids are likely to share similar recognition characteristics. In addition, the results provide a rational background for the evaluation of antibody specificity and the interpretation of results in immunocytochemical studies using antisera to glutamate and aspartate.
通过酶免疫测定法，分别测量大量选定的半抗原对两种抗谷氨酸和两种抗天冬氨酸血清中谷氨酸和天冬氨酸结合的取代情况，确定了兔体内针对L-谷氨酸和L-天冬氨酸戊二醛缀合物产生的抗体对半抗原识别的分子要求。结果表明，氨基酸的N端修饰，如存在N-乙酰基或N-氨甲酰基，或添加第二个氨基酸以形成与C端谷氨酸或天冬氨酸的二肽，在不同程度上是可以耐受的，天冬氨酸抗血清比谷氨酸抗血清的耐受性更强。这些抗体对两种氨基酸中存在的两个羧基具有点对点识别位点。由于任何一种抗体都不能识别适当的D立体异构体，提示氨基酸与其各自结合位点之间存在很强的形状互补性。两个羧基之间距离的改变，或其中一个或两个羧基的修饰、置换或缺失，都会强烈降低或消除结合。基于这些结果，我们认为针对这些氨基酸类似缀合物产生的其他抗体可能具有相似的识别特征。此外，这些结果为评估抗体特异性以及解释使用谷氨酸和天冬氨酸抗血清的免疫细胞化学研究结果提供了合理的背景。
