Fassina G, Chaiken I M
National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892.
J Mol Recognit. 1989 Apr;1(4):158-65. doi: 10.1002/jmr.300010403.
The self-assembly properties of the arginine 8-vasopressin/bovine neurophysin II (AVP/BNPII) biosynthetic precursor were studied using glycopeptide-deleted and sequence-redesigned semisynthetic derivatives. Semisynthetic precursors were prepared by chemically coupling synthetic vasopressinyl sequence domains and native protein-derived neurophysin II domain. Measurement of precursor-protein association by the extent of affinity chromatographic retardation on agarose-immobilized BNPII verified that the semisynthetic precursor with native AVP sequence has an enhanced self-association propensity similar to that predicted for native precursor. Here, the stabilizing contacts between hormone and neurophysin domains, mainly the positively charged protonated alpha-amino group and tyrosyl 2 side chain of the hormone, are retained. Semisynthetic precursor variants in which the hormone domain is sequence-simplified by introducing alanyl residues in positions not considered important for neurophysin recognition show non-reduced association to BNPII. In contrast, removal of one of the main contact elements between hormone and neurophysin by acetylation of the hormone alpha-amino group abolishes potentiation of precursor self-association. The results show that the presence of the C-terminal glycopeptide sequence domain of native vasopressin precursor is not required to promote self-assembly of the precursor. The data verify the view proposed for the oxytocinyl precursor that intramolecular domain interaction is the triggering event which promotes the increase in affinity of precursor self-association (intermolecular self-recognition). The data also define some of the intramolecular self-recognition elements in the folded precursor required for the high affinity intermolecular self-recognition.
利用糖肽缺失和序列重新设计的半合成衍生物，研究了精氨酸8 - 加压素/牛神经垂体素II（AVP/BNPII）生物合成前体的自组装特性。半合成前体通过化学偶联合成的加压素序列结构域和天然蛋白质衍生的神经垂体素II结构域制备。通过琼脂糖固定的BNPII上亲和色谱阻滞程度来测量前体 - 蛋白质结合，证实具有天然AVP序列的半合成前体具有增强的自缔合倾向，类似于天然前体的预测值。在此，激素和神经垂体素结构域之间的稳定接触得以保留，主要是激素带正电荷的质子化α - 氨基和酪氨酸2侧链。通过在对神经垂体素识别不重要的位置引入丙氨酰残基来简化激素结构域的半合成前体变体，显示出与BNPII的结合未降低。相反，通过对激素α - 氨基进行乙酰化去除激素和神经垂体素之间的主要接触元件之一，消除了前体自缔合的增强作用。结果表明，天然加压素前体的C末端糖肽序列结构域的存在并非促进前体自组装所必需。这些数据证实了对催产素前体提出的观点，即分子内结构域相互作用是促进前体自缔合亲和力增加（分子间自我识别）的触发事件。这些数据还确定了折叠前体中高亲和力分子间自我识别所需的一些分子内自我识别元件。
