Comparative analysis of membrane-associated fusion peptide secondary structure and lipid mixing function of HIV gp41 constructs that model the early pre-hairpin intermediate and final hairpin conformations.
Comparative analysis of membrane-associated fusion peptide secondary structure and lipid mixing function of HIV gp41 constructs that model the early pre-hairpin intermediate and final hairpin conformations.
复制标题
对模拟早期发夹前中间体和最终发夹构象的 HIV gp41 构建体的膜相关融合肽二级结构和脂质混合功能进行比较分析。
DOI：
10.1016/j.jmb.2010.01.018
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发表时间：
2010
影响因子：
5.6
通讯作者：
Weliky,DavidP
中科院分区：
文献类型：
--
作者：
Sackett,Kelly;Nethercott,MatthewJ;Epand,RaquelF;Epand,RichardM;Kindra,DouglasR;Shai,Yechiel;Weliky,DavidP
病毒和宿主细胞膜之间的融合是人类免疫缺陷病毒感染的初始步骤，并且由包埋在病毒膜中的gp 41蛋白介导。gp 41的N-末端融合肽（FP）区与宿主细胞膜结合，并在融合催化中起关键作用。关键的gp 41融合构象包括早期前发夹中间体（PHI），其特征在于FP的C末端区域中的延伸卷曲螺旋结构和具有紧凑的六螺旋束结构的最终发夹状态。本研究的大“N70”（gp 411 -70）和“FP-发夹”构建体含有FP并分别模拟了PHI和发夹构象。还与较短的“FP 34”（gp 411 -34）片段进行了比较。在具有生理相关胆固醇含量的膜和不含胆固醇的膜中进行了研究。在任一种膜类型中，构建体之间的融合功能存在很大差异，其中FP-发夹诱导的融合很少，FP 34诱导的融合中等，N70诱导的融合非常快速。总体而言，我们的研究结果支持加速gp 41诱导的膜融合的早期PHI构象和融合后逮捕折叠到最终的六螺旋束结构。通过固态核磁共振探测膜结合构建体的Leu 7处的FP二级结构，并显示具有β-折叠或螺旋结构的分子群体，其中对于FP 34观察到比N70或FP-发夹结构更大的β-折叠群体。构建体之间融合功能的巨大差异与FP二级结构无明显相关性。对促融合FP 34和N70的胆固醇依赖性FP结构和非促融合FP-发夹的胆固醇非依赖性结构的观察与FP 34和N70的FP的膜插入一致，并且与FP-发夹的插入缺乏一致。因此，FP的膜插入可能与早期的PHI构象和FP撤回与最终的发夹构象。
Fusion between viral and host cell membranes is the initial step of human immunodeficiency virus infection and is mediated by the gp41 protein, which is embedded in the viral membrane. The ∼20-residue N-terminal fusion peptide (FP) region of gp41 binds to the host cell membrane and plays a critical role in fusion catalysis. Key gp41 fusion conformations include an early pre-hairpin intermediate (PHI) characterized by extended coiled-coil structure in the region C-terminal of the FP and a final hairpin state with compact six-helix bundle structure. The large “N70” (gp41 1–70) and “FP-Hairpin” constructs of the present study contained the FP and respectively modeled the PHI and hairpin conformations. Comparison was also made to the shorter “FP34” (gp41 1–34) fragment. Studies were done in membranes with physiologically relevant cholesterol content and in membranes without cholesterol. In either membrane type, there were large differences in fusion function among the constructs with little fusion induced by FP-Hairpin, moderate fusion for FP34, and very rapid fusion for N70. Overall, our findings support acceleration of gp41-induced membrane fusion by early PHI conformation and fusion arrest after folding to the final six-helix bundle structure. FP secondary structure at Leu7 of the membrane-associated constructs was probed by solid-state nuclear magnetic resonance and showed populations of molecules with either β-sheet or helical structure with greater β-sheet population observed for FP34 than for N70 or FP-Hairpin. The large differences in fusion function among the constructs were not obviously correlated with FP secondary structure. Observation of cholesterol-dependent FP structure for fusogenic FP34 and N70 and cholesterol-independent structure for non-fusogenic FP-Hairpin was consistent with membrane insertion of the FP for FP34 and N70 and with lack of insertion for FP-Hairpin. Membrane insertion of the FP may therefore be associated with the early PHI conformation and FP withdrawal with the final hairpin conformation.