Tampé R, Clark B R, McConnell H M
Stauffer Laboratory for Physical Chemistry, Stanford University, CA 94305.
Science. 1991 Oct 4;254(5028):87-9. doi: 10.1126/science.1656526.
The 17-amino acid peptide from chicken ovalbumin, Ova(323-339), was labeled at the amino terminus with fluorescein [FOva(323-339)] and near the carboxyl terminus with Texas Red [AcOva(323-338)KTR]. Fluorescence spectroscopy was carried out on resolved electrophoretic bands on nonreducing polyacrylamide gels derived from incubation mixtures containing major histocompatibility complex (MHC) class II molecules IAd and the FOva(323-339)- and AcOva(323-338)KTR-labeled peptides. Energy transfer between fluorescein and Texas Red was observed in the "floppy" alpha beta heterodimer band, but not in the "compact" alpha beta heterodimer band. Energy transfer was detected between the truncated peptides FOva(323-328)CONH2 and AcOva(331-338)KTR in both the compact alpha beta and floppy alpha beta gel bands. The energy-transfer data suggest that the two binding sites of floppy alpha beta arise from splitting apart a putative large, single binding site region in compact alpha beta.
来自鸡卵清蛋白的17个氨基酸的肽段Ova(323 - 339)，在氨基末端用荧光素标记[FOva(323 - 339)]，在羧基末端附近用德克萨斯红标记[AcOva(323 - 338)KTR]。荧光光谱法是对来自含有主要组织相容性复合体（MHC）II类分子IAd以及FOva(323 - 339)和AcOva(323 - 338)KTR标记肽段的孵育混合物的非还原聚丙烯酰胺凝胶上分离的电泳条带进行的。在“松弛型”αβ异二聚体条带中观察到了荧光素和德克萨斯红之间的能量转移，但在“紧密型”αβ异二聚体条带中未观察到。在紧密型αβ和松弛型αβ凝胶条带中均检测到截短肽段FOva(323 - 328)CONH2和AcOva(331 - 338)KTR之间的能量转移。能量转移数据表明，松弛型αβ的两个结合位点是由紧密型αβ中一个假定的大的单一结合位点区域分裂而成的。
