Huang Shenstone, Green Bryan, Thompson Megan, Chen Richard, Thomaston Jessica, DeGrado William F, Howard Kathleen P
Department of Chemistry and Biochemistry, Swarthmore College, Swarthmore, Pennsylvania, 19081.
Protein Sci. 2015 Mar;24(3):426-9. doi: 10.1002/pro.2631. Epub 2015 Jan 14.
The influenza A M2 protein is a 97-residue integral membrane protein involved in viral budding and proton conductance. Although crystal and NMR structures exist of truncated constructs of the protein, there is disagreement between models and only limited structural data are available for the full-length protein. Here, the structure of the C-terminal juxtamembrane region (sites 50-60) is investigated in the full-length M2 protein using site-directed spin-labeling electron paramagnetic resonance (EPR) spectroscopy in lipid bilayers. Sites 50-60 were chosen for study because this region has been shown to be critical to the role the M2 protein plays in viral budding. Continuous wave EPR spectra and power saturation data in the presence of paramagnetic membrane soluble oxygen are consistent with a membrane surface associated amphipathic helix. Comparison between data from the C-terminal juxtamembrane region in full-length M2 protein with data from a truncated M2 construct demonstrates that the line shapes and oxygen accessibilities are remarkably similar between the full-length and truncated form of the protein.
甲型流感病毒M2蛋白是一种由97个氨基酸组成的整合膜蛋白，参与病毒出芽和质子传导。尽管已有该蛋白截短结构的晶体结构和核磁共振结构，但不同模型之间存在分歧，且关于全长蛋白的结构数据有限。在此，利用脂质双层中的定点自旋标记电子顺磁共振（EPR）光谱，对全长M2蛋白的C端近膜区（50-60位点）结构进行了研究。选择50-60位点进行研究是因为该区域已被证明对M2蛋白在病毒出芽中所起的作用至关重要。在存在顺磁性膜可溶性氧的情况下，连续波EPR光谱和功率饱和数据与膜表面相关的两亲性螺旋一致。全长M2蛋白C端近膜区的数据与截短的M2构建体的数据比较表明，该蛋白的全长形式和截短形式之间的线形和氧可及性非常相似。
