Johnson J G, Cross G A
Biochem J. 1979 Mar 15;178(3):689-97. doi: 10.1042/bj1780689.
Two conformationally distinct regions were revealed by tryptic cleavage of six undenatured variant surface glycoproteins purified from clones of Trypanosoma brucei. Within 5 min, the native glycoproteins (65,000 mol.wt.) were cleaved, yielding a large N-terminal fragment (48,000-55,000 mol.wt. depending on the variant) together with one or more C-terminal fragments. After 30-60 min incubation, further breakdown of the large fragment occurred in some variants. The ultimate large product (40,000-52,000 mol.wt.) was very resistant to further degradation by trypsin (in the absence of denaturation). The distinction between N-terminal and C-terminal domains may be significant in relation to the organization and function of these glycoproteins on the trypanosome surface.
通过对从布氏锥虫克隆中纯化得到的六种未变性的变异表面糖蛋白进行胰蛋白酶切割，发现了两个构象不同的区域。在5分钟内，天然糖蛋白（分子量65,000）被切割，产生一个大的N端片段（分子量48,000 - 55,000，取决于变体）以及一个或多个C端片段。孵育30 - 60分钟后，一些变体中的大片段进一步分解。最终的大片段产物（分子量40,000 - 52,000）对胰蛋白酶的进一步降解具有很强的抗性（在未变性的情况下）。N端和C端结构域之间的差异可能与这些糖蛋白在锥虫表面的组织和功能有关。
