LINE BROADENING MECHANISMS IN LANTHANIDE DOPED PHOSPHOLIPID MEMBRANES

囊膜糖蛋白41,000的N-端22个残基 HIV(Gp41)与病毒的融合过程有关 靶细胞膜。此gp41融合肽(Fp)具有高度的 保守的疏水序列，包含一个串联重复序列 三肽Phe-Leu-Gly，与融合多肽具有广泛的同源性 其他副粘病毒。FTIR和CD研究及理论 计算表明gp41FP插入到磷脂中 膜呈斜角，残基519至533呈a-螺旋 构象，剩余的多肽呈随机构象。 15N标记gp41FP的固体核磁共振研究 为确定这一模型的准确性进行了调查。请愿书是 被结合到脂质双层中，并在玻璃板上定向。这个 Ala-524位置标记gp41 FP的~(15)N化学位移光谱 表示酰胺键与螺旋轴平行定向。 回到正常的双层结构。Ala-253和Gly-254的15N谱 反映随机构象和跨膜构象的混合物 预计为构象过渡带。ALA-539给出了一个 无规构象的15N光谱特征。

The N-terminal 22 residues of the envelope glycoprotein 41,000 (gp41) of HIV have been implicated in the process of viral fusion with the target cell membrane. This gp41 fusion peptide (FP) has a highly conserved hydrophobic sequence, containing a tandem repeat of the tripeptide Phe-Leu-Gly, with extensive homology to the fusion peptides of other paramyxoviruses. FTIR and CD studies and theoretical calculations suggest that the gp41 FP inserts into the phospholipid membrane at an oblique angle, with residues 519 to 533 in an a-helical conformation, and the remaining peptide in a random conformation. Solid-state NMR studies of the selectively 15N labeled gp41 FP were conducted to ascertain the veracity of this model. The petide was incorporated into lipid bilayers and oriented on glass plates. The 15N chemical shift spectrum of gp41 FP labeled in position Ala-524 indicates that the amide bond is oriented with the helix axis paralell to the bilayer normal. The 15N spectra from Ala-253 and Gly-254 reflect a mixture of random and transmembrane conformations, as might be expected for a conformational transition zone. Ala-539 gives an 15N spectrum characteristic of random conformation.