NMR structures of fusion peptide from influenza hemagglutinin H3 subtype and its mutants
NMR structures of fusion peptide from influenza hemagglutinin H3 subtype and its mutants
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DOI：
10.1002/psc.2616
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发表时间：
2014-04-01
影响因子：
2.1
通讯作者：
Liu, Maili
中科院分区：
文献类型：
--
作者：
Du, Tianpeng;Jiang, Ling;Liu, Maili
位于血凝素HA 2亚基N-末端的流感融合肽启动病毒膜与宿主细胞内体膜的融合过程。有报道H3亚型20个氨基酸残基的融合肽（H3-HAfp 20）与H1亚型23个氨基酸残基的融合肽（H1-HAfp 23）的结构存在显著差异。H1和H3亚型的第12和15位残基之间的序列差异不能完全解释构象变化。H3-HAfp 23中参与氢键形成的前三个和后三个氨基酸可能在融合过程中发挥重要作用。为了证实这一假设，我们研究的H3-HAfp 23肽及其突变体，G1 S和G1 V，在十二烷基磷脂酰胆碱胶束的结构，通过使用异频NMR技术。结果表明，H3-HAfp 23与H1-HAfp 23相似，但与H3-HAfp 20显著不同，H3-HAfp 23也具有紧密的螺旋发夹结构，其N-和C-末端连接在一起，这是因为Gly（1）与最后三个氨基酸Trp（21）-Tyr（22）-Gly（23）之间存在氢键。虽然“半融合”G1 S和致死性G1 V突变体具有发夹状螺旋结构，但N-和C-末端之间的距离由于氢键的短缺和反平行螺旋之间较大的扭结角而增加。顺磁离子滴定实验表明，末端插入作为溶解介质的十二烷基磷脂酰胆碱胶束中。这可能暗示紧密的螺旋发夹结构，特别是末端的封闭构象，在融合活性中起重要作用。版权所有（c）2014 European Peptide Society and John Wiley & Sons，Ltd.
The influenza fusion peptide located at the N-terminus of the hemagglutinin HA2 subunit initiates the fusing process of the viral membrane with the host cell endosomal membrane. It had been reported that the structure of a 20-residue H3 subtype fusion peptide (H3-HAfp20) was significantly different with that of a H1 subtype 23-residue one (H1-HAfp23). The sequential difference between the 12th and 15th residues of H1 and H3 subtypes could not fully explain the conformational variation. The first and last three amino acids of H3-HAfp23 involved in formation of hydrogen bonds may play an important role in fusion process. To confirm this hypothesis, we investigate the structures of H3-HAfp23 peptide and its mutants, G1S and G1V, in dodecylphosphatidyl choline micelles by using heteronuclear NMR technology. The results demonstrate that, similar to H1-HAfp23 but significantly different with H3-HAfp20, H3-HAfp23 also has tight helical hairpin structure with the N- and C-terminuses linked together because of the hydrogen bonds between Gly(1) and the last three amino acids, Trp(21)―Tyr(22)―Gly(23). Although the 'hemifusion' G1S and lethal G1V mutants have hairpin-like helical structures, the distances between the N- and C-terminuses are increased as shortage of the hydrogen bonds and the larger kink angle between the antiparallel helices. The paramagnetic ion titration experiments show that the terminuses are inserted into the dodecylphosphatidyl choline micelles used as solving media. These may imply that the tight helical hairpin structure, especially the closed conformation at terminus, plays an important role in fusion activity. Copyright (c) 2014 European Peptide Society and John Wiley & Sons, Ltd.