ジャーナル: PLoS One / 年: 2014 タイトル: Cryo-EM structure of isomeric molluscan hemocyanin triggered by viral infection. 著者: Hongtao Zhu / Jun Zhuang / Hongli Feng / Rongfeng Liang / Jiangyong Wang / Lianhui Xie / Ping Zhu / 要旨: Hemocyanins (Hcs) of arthropods and mollusks function not only as oxygen transporters, but also as phenoloxidases (POs). In invertebrates, PO is an important component in the innate immune cascade, ...Hemocyanins (Hcs) of arthropods and mollusks function not only as oxygen transporters, but also as phenoloxidases (POs). In invertebrates, PO is an important component in the innate immune cascade, where it functions as the initiator of melanin synthesis, a pigment involved in encapsulating and killing of pathogenic microbes. Although structures of Hc from several species of invertebrates have been reported, the structural basis for how PO activity is triggered by structural changes of Hc in vivo remains poorly understood. Here, we report a 6.8 Å cryo-electron microscopy (cryo-EM) structure of the isomeric form of hemocyanin, which was isolated from Abalone Shriveling syndrome-associated Virus (AbSV) infected abalone (Halitotis diversicolor), and build a pseudoatomic model of isomeric H. diversicolor hemocyanin 1 (HdH1). Our results show that, compared with native form of HdH1, the architecture of isomeric HdH1 turns into a more relaxed form. The interactions between certain functional units (FUs) present in the native form of Hc either decreased or were totally abolished in the isomeric form of Hc. As a result of that, native state Hc switches to its isomeric form, enabling it to play its role in innate immune responses against invading pathogens.
EMAN2 was initially used for particle picking, 2D classification, projection refinement and 3D reconstruction for both normal and isomeric hemocyanins with C5 symmetry imposed. Subsequently, 57,043 isomeric hemocyanin particles were imported to Relion-1.1 for further refinement and reconstruction by applying D5 symmetry, using the reconstructed map from EMAN2 as the initial model. Xmipp-2.4 was used for the? bfactor correction to generate the final 3D reconstruction map of isomeric hemocyanin.
CTF補正
詳細: Each particle
最終 再構成
想定した対称性 - 点群: D5 (2回x5回 2面回転対称) アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 6.8 Å / 解像度の算出法: OTHER / ソフトウェア - 名称: EMAN2, Relion-1.1, Xmipp-2.4 / 使用した粒子像数: 57043