Selmani Veli, Robbins Kevin J, Ivancic Valerie A, Lazo Noel D
Carlson School of Chemistry and Biochemistry, Clark University, Worcester, Massachusetts, 01610.
Protein Sci. 2015 Mar;24(3):420-5. doi: 10.1002/pro.2620. Epub 2015 Jan 13.
Cationic amyloid fibrils found in human semen enhance the transmission of the human immunodeficiency virus (HIV) and thus, are named semen-derived enhancer of virus infection (SEVI). The mechanism for the enhancement of transmission is not completely understood but it has been proposed that SEVI neutralizes the repulsion that exists between the negatively charged viral envelope and host cell membrane. Consistent with this view, here we show that the fluorescence of cationic thioflavin T (ThT) in the presence of SEVI is weak, and thus ThT is not an efficient detector of SEVI. On the other hand, K114 ((trans, trans)-bromo-2,5-bis(4-hydroxystyryl)benzene) forms a highly fluorescent, phenolate-like species on the cationic surface of SEVI. This species does not form in the presence of amyloid fibrils from insulin and amyloid-β protein, both of which are efficiently detected by ThT fluorescence. Together, our results show that K114 is an efficient detector of SEVI.
在人类精液中发现的阳离子淀粉样纤维可增强人类免疫缺陷病毒（HIV）的传播，因此被命名为病毒感染精液衍生增强因子（SEVI）。其增强传播的机制尚未完全明确，但有观点认为，SEVI可中和带负电荷的病毒包膜与宿主细胞膜之间存在的排斥力。与此观点一致的是，我们在此表明，在SEVI存在的情况下，阳离子硫黄素T（ThT）的荧光较弱，因此ThT并非SEVI的有效检测剂。另一方面，K114（（反，反）-溴-2,5-双（4-羟基苯乙烯基）苯）在SEVI的阳离子表面形成一种高荧光的酚盐样物质。在胰岛素和淀粉样β蛋白的淀粉样纤维存在时，该物质不会形成，而这两种物质均可通过ThT荧光有效检测。总之，我们的结果表明，K114是SEVI的有效检测剂。
