ジャーナル: Elife / 年: 2014 タイトル: Stepwise visualization of membrane pore formation by suilysin, a bacterial cholesterol-dependent cytolysin. 著者: Carl Leung / Natalya V Dudkina / Natalya Lukoyanova / Adrian W Hodel / Irene Farabella / Arun P Pandurangan / Nasrin Jahan / Mafalda Pires Damaso / Dino Osmanović / Cyril F Reboul / Michelle ...著者: Carl Leung / Natalya V Dudkina / Natalya Lukoyanova / Adrian W Hodel / Irene Farabella / Arun P Pandurangan / Nasrin Jahan / Mafalda Pires Damaso / Dino Osmanović / Cyril F Reboul / Michelle A Dunstone / Peter W Andrew / Rana Lonnen / Maya Topf / Helen R Saibil / Bart W Hoogenboom / 要旨: Membrane attack complex/perforin/cholesterol-dependent cytolysin (MACPF/CDC) proteins constitute a major superfamily of pore-forming proteins that act as bacterial virulence factors and effectors in ...Membrane attack complex/perforin/cholesterol-dependent cytolysin (MACPF/CDC) proteins constitute a major superfamily of pore-forming proteins that act as bacterial virulence factors and effectors in immune defence. Upon binding to the membrane, they convert from the soluble monomeric form to oligomeric, membrane-inserted pores. Using real-time atomic force microscopy (AFM), electron microscopy (EM), and atomic structure fitting, we have mapped the structure and assembly pathways of a bacterial CDC in unprecedented detail and accuracy, focussing on suilysin from Streptococcus suis. We show that suilysin assembly is a noncooperative process that is terminated before the protein inserts into the membrane. The resulting ring-shaped pores and kinetically trapped arc-shaped assemblies are all seen to perforate the membrane, as also visible by the ejection of its lipids. Membrane insertion requires a concerted conformational change of the monomeric subunits, with a marked expansion in pore diameter due to large changes in subunit structure and packing.
名称: Suilysin / タイプ: sample / ID: 1000 詳細: The protein was incubated with lipid vesicles (PC:Cholesterol, molar ratio 45:55) for 10 minutes at 37oC 集合状態: 37 / Number unique components: 1
分子量
実験値: 2.072 MDa / 理論値: 2.072 MDa / 手法: Calculated from the molecular weight of the monomer
凍結剤: ETHANE / チャンバー内湿度: 100 % / チャンバー内温度: 91 K / 装置: FEI VITROBOT MARK III 手法: Liposomes with the protein were applied to glow-discharged lacey carbon coated copper grids and blotted for 5 s.
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電子顕微鏡法
顕微鏡
FEI POLARA 300
温度
最低: 80 K / 最高: 90 K / 平均: 85 K
アライメント法
Legacy - 非点収差: Objective lens astigmatism was corrected at 150,000x magnification
37-fold symmetrised reconstruction. Image regions containing the pores with small surrounding areas of membrane were selected manually using Boxer (EMAN 1.9) software.
CTF補正
詳細: Phase flipping for each particle
最終 再構成
想定した対称性 - 点群: C37 (37回回転対称) / アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 15.0 Å / 解像度の算出法: OTHER / ソフトウェア - 名称: SPIDER, IMAGIC, EMAN / 詳細: Final maps were calculated by BP RP in SPIDER / 使用した粒子像数: 600