Alfadhli Ayna, Steel Eric, Finlay Liam, Bächinger Hans Peter, Barklis Eric
Department of Microbiology, Vollum Institute, Oregon Health & Sciences University, Portland, OR 97201-3098, USA.
J Biol Chem. 2002 Jul 26;277(30):27103-8. doi: 10.1074/jbc.M203395200. Epub 2002 May 17.
The nucleocapsid (N) proteins of hantaviruses such as the Sin Nombre virus (SNV) bind to membranes and viral RNAs, associate with transcription and replication complexes, and oligomerize during the process of virus assembly. N proteins trimerize in vitro and in vivo, and associate via assembly domains at their amino- and carboxyl-terminal ends. Because structure prediction algorithms suggested that N protein residues 3-75 form two coiled-coil motifs separated by an intervening kink or turn sequence, we examined the properties of peptides representing SNV N protein residues 3-35, 43-75, and 3-75. Of the three peptides, N-(3-35) assembled coiled-coil oligomers only at high concentration and low temperature. In contrast, N-(43-75) efficiently trimerized at low concentration, implying that it carries a coiled-coil trigger sequence. Interestingly, while the longer peptide, N-(3-75), assembled dimers and/or trimers at high concentration, at low concentration it appeared to adopt an intramolecular helix-turn-helix conformation. These results suggest that N protein oligomerization involves the bundling of intramolecular antiparallel coils or a conformational switch from intra- to intermolecular coiled-coils.
汉坦病毒（如辛诺柏病毒，SNV）的核衣壳（N）蛋白可与细胞膜和病毒RNA结合，与转录和复制复合体相互作用，并在病毒组装过程中发生寡聚化。N蛋白在体外和体内均会三聚化，并通过其氨基末端和羧基末端的组装结构域相互结合。由于结构预测算法表明N蛋白的3 - 75位残基形成了两个卷曲螺旋基序，中间由一个扭结或转角序列隔开，因此我们研究了代表SNV N蛋白3 - 35位、43 - 75位和3 - 75位残基的肽段的特性。在这三个肽段中，N -（3 - 35）仅在高浓度和低温下组装形成卷曲螺旋寡聚体。相比之下，N -（43 - 75）在低浓度下就能高效三聚化，这意味着它携带一个卷曲螺旋触发序列。有趣的是，较长的肽段N -（3 - 75）在高浓度下组装形成二聚体和/或三聚体，而在低浓度下它似乎采用分子内螺旋 - 转角 - 螺旋构象。这些结果表明，N蛋白的寡聚化涉及分子内反平行螺旋的捆绑，或者是从分子内卷曲螺旋到分子间卷曲螺旋的构象转换。
