Fontenot J D, Mariappan S V, Catasti P, Domenech N, Finn O J, Gupta G
Theoretical Biology and Biophysics, Los Alamos National Laboratory, NM 87545, USA.
J Biomol Struct Dyn. 1995 Oct;13(2):245-60. doi: 10.1080/07391102.1995.10508837.
Human mucins are T or S glycosylated tandem repeat proteins. In breast cancer, mucins become under or unglycosylated. Two-dimensional nuclear magnetic resonance experiments are performed on chemically synthesized mucin tandem repeat polypeptides, (PDTRPAPGST-APPAHGVTSA)n the unglycosylated form for n=1,3 where (APDTR) constitutes the antigenic sites for the antibodies isolated form the tumors in the breast cancer patients. These studies demonstrate how the tandem repeats assemble in space giving rise to the overall tertiary structure, and the local structure and presentation of the antigenic site(APDTR) at the junction of two neighboring repeats. The NMR data reveal repeating knob-like structures connected by extended spacers. The knobs protrude away from the long-axis of Muc-1 and the predominant antigenic site (APDTR) forms the accessible tip of the knob. Multiple tandem repeats enhance the rigidity and presentation of the knob-like structures.
人黏蛋白是T或S糖基化的串联重复蛋白。在乳腺癌中，黏蛋白会发生糖基化不足或未糖基化的情况。对化学合成的黏蛋白串联重复多肽（PDTRPAPGST-APPAHGVTSA）n进行二维核磁共振实验，该多肽为未糖基化形式，n = 1,3，其中（APDTR）构成了从乳腺癌患者肿瘤中分离出的抗体的抗原位点。这些研究展示了串联重复序列如何在空间中组装形成整体三级结构，以及抗原位点（APDTR）在两个相邻重复序列交界处的局部结构和呈现方式。核磁共振数据揭示了由延伸的间隔区连接的重复旋钮状结构。这些旋钮从Muc-1的长轴向外突出，主要抗原位点（APDTR）形成了旋钮可及的尖端。多个串联重复序列增强了旋钮状结构的刚性和呈现效果。
