LINE BROADENING MECHANISMS IN LANTHANIDE DOPED PHOSPHOLIPID MEMBRANES

包膜糖蛋白41，000的N-末端22个残基 （gp 41）的HIV病毒融合的过程中， 靶细胞膜。 该gp 41融合肽（FP）具有高度的 保守的疏水序列，含有一个串联重复的 三肽Phe-Leu-Gly，与融合肽具有广泛的同源性 其他副粘病毒。 FTIR和CD研究和理论 计算表明，gp 41 FP插入到磷脂中， 膜在斜角，与残基519至533在一个α-螺旋 构象，并且剩余的肽处于随机构象。 对选择性15 N标记的gp 41 FP进行了固态NMR研究。 以确定该模型的准确性。 肽是 掺入脂质双层中并在玻璃板上取向。 的 Ala-524位标记的gp 41 FP的15 N化学位移谱 表明酰胺键的取向与螺旋轴平行 双层正常。 Ala-253和Gly-254的15 N光谱 反映了随机和跨膜构象的混合物，可能 可能是构象过渡区。 Ala-539给出了一种 15 N光谱特征的随机构象。

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.