Midoux P, Kichler A, Boutin V, Maurizot J C, Monsigny M
Centre de Biophysique Moléculaire, CNRS et Université d'Orléans, France.
Bioconjug Chem. 1998 Mar-Apr;9(2):260-7. doi: 10.1021/bc9701611.
We designed a peptide, H5WYG (GLFHAIAHFIHGGWHGLIHGWYG), that permeabilizes cell membrane at a slightly acidic pH but not at neutral pH. Absorbance, fluorescence, and circular dichroism spectra showed that H5WYG undergoes a dramatic conformational change between pH 7.0 and 6.0 that correlates with the protonation of the histidyl residues. Cell permeabilization studies monitored by flow cytometry on living cells showed that H5WYG permeabilizes the cell membrane with a great efficiency at pH 6.4 but was not active at neutral pH; at pH 6.8, the peptide permeabilized 50% of the cells at 20 degrees C within 10 min. H5WYG increased the expression of genes transferred to cells as glycosylated polylysine-DNA complexes, and the transfection efficiency was not impaired in the presence of serum. Therefore, this peptide containing several histidines that become positively charged when the pH decreased to less than 7.0 is a suitable helper for delivering molecules into the cytosol upon either permeabilization of the plasma membrane induced by lowering the extracellular medium to pH 6.4 or permeabilization of the endosomal membrane induced by acidification of endosomes.
我们设计了一种肽，即H5WYG（GLFHAIAHFIHGGWHGLIHGWYG），它在略酸性pH条件下可使细胞膜通透，但在中性pH条件下则不能。吸光度、荧光和圆二色光谱表明，H5WYG在pH 7.0和6.0之间发生了显著的构象变化，这与组氨酸残基的质子化有关。通过流式细胞术对活细胞进行的细胞膜通透化研究表明，H5WYG在pH 6.4时能高效地使细胞膜通透，但在中性pH时无活性；在pH 6.8时，该肽在20℃下10分钟内可使50%的细胞通透。H5WYG增加了作为糖基化聚赖氨酸 - DNA复合物转移到细胞中的基因的表达，并且在有血清存在的情况下转染效率并未受损。因此，这种含有多个组氨酸的肽在将细胞外培养基pH降低至6.4诱导质膜通透或内体酸化诱导内体膜通透时，是一种将分子递送至细胞质的合适辅助剂，当pH降至小于7.0时，这些组氨酸会带正电荷。
