Miller M A, Cloyd M W, Liebmann J, Rinaldo C R, Islam K R, Wang S Z, Mietzner T A, Montelaro R C
Department of Molecular Genetics and Biochemistry, University of Pittsburgh School of Medicine, Pennsylvania 15261.
Virology. 1993 Sep;196(1):89-100. doi: 10.1006/viro.1993.1457.
Previously we reported that synthetic peptide homologs of an amphipathic region (designated the lentivirus lytic peptide, or LLP-1) near the carboxy terminus of HIV-1 transmembrane protein (TM) were toxic for both prokaryotic and eukaryotic cells when added exogenously to cell cultures. We postulated that these peptides may exert their toxic effects in much the same manner as natural cytolytic peptides such as magainins, cecropins, and melittin by forming pores through cellular membranes. Here we show the results of 51Cr-release assays and membrane flux measurements of peptide treated cells that support our hypothesis. We have also tested a limited panel of LLP-1 peptide analogs in these assays and found that relatively minor alterations in peptide charge or amphipathicity in the parent HIV LLP-1 sequence resulted in total loss of membrane perturbative properties. These results demonstrate that the peptide homolog of HIV-1 LLP-1 can indeed perturb membranes by forming pores of defined size in cytoplasmic membranes. Furthermore, the analog studies described here reveal that the amphipathy and high positive charge of this protein segment are required for the membrane perturbative properties.
此前我们报道，在HIV-1跨膜蛋白（TM）羧基末端附近的一个两亲区域（命名为慢病毒裂解肽，或LLP-1）的合成肽类似物，当外源添加到细胞培养物中时，对原核细胞和真核细胞均有毒性。我们推测，这些肽可能通过在细胞膜上形成孔道，以与天然溶细胞肽（如蛙皮素、天蚕素和蜂毒素）非常相似的方式发挥其毒性作用。在此我们展示了支持我们假设的肽处理细胞的51Cr释放试验和膜通量测量结果。我们还在这些试验中测试了一组有限的LLP-1肽类似物，发现母体HIV LLP-1序列中肽电荷或两亲性的相对微小改变会导致膜扰动特性完全丧失。这些结果表明，HIV-1 LLP-1的肽类似物确实可以通过在细胞质膜上形成特定大小的孔道来扰动膜。此外，此处描述的类似物研究表明，该蛋白质片段的两亲性和高正电荷是膜扰动特性所必需的。
