ジャーナル: Nature / 年: 2016 タイトル: Structure- and function-based design of Plasmodium-selective proteasome inhibitors. 著者: Hao Li / Anthony J O'Donoghue / Wouter A van der Linden / Stanley C Xie / Euna Yoo / Ian T Foe / Leann Tilley / Charles S Craik / Paula C A da Fonseca / Matthew Bogyo / 要旨: The proteasome is a multi-component protease complex responsible for regulating key processes such as the cell cycle and antigen presentation. Compounds that target the proteasome are potentially ...The proteasome is a multi-component protease complex responsible for regulating key processes such as the cell cycle and antigen presentation. Compounds that target the proteasome are potentially valuable tools for the treatment of pathogens that depend on proteasome function for survival and replication. In particular, proteasome inhibitors have been shown to be toxic for the malaria parasite Plasmodium falciparum at all stages of its life cycle. Most compounds that have been tested against the parasite also inhibit the mammalian proteasome, resulting in toxicity that precludes their use as therapeutic agents. Therefore, better definition of the substrate specificity and structural properties of the Plasmodium proteasome could enable the development of compounds with sufficient selectivity to allow their use as anti-malarial agents. To accomplish this goal, here we use a substrate profiling method to uncover differences in the specificities of the human and P. falciparum proteasome. We design inhibitors based on amino-acid preferences specific to the parasite proteasome, and find that they preferentially inhibit the β2-subunit. We determine the structure of the P. falciparum 20S proteasome bound to the inhibitor using cryo-electron microscopy and single-particle analysis, to a resolution of 3.6 Å. These data reveal the unusually open P. falciparum β2 active site and provide valuable information about active-site architecture that can be used to further refine inhibitor design. Furthermore, consistent with the recent finding that the proteasome is important for stress pathways associated with resistance of artemisinin family anti-malarials, we observe growth inhibition synergism with low doses of this β2-selective inhibitor in artemisinin-sensitive and -resistant parasites. Finally, we demonstrate that a parasite-selective inhibitor could be used to attenuate parasite growth in vivo without appreciable toxicity to the host. Thus, the Plasmodium proteasome is a chemically tractable target that could be exploited by next-generation anti-malarial agents.
全体 : Plasmodium falciparum 20S proteasome core bound to a specific inh...
全体
名称: Plasmodium falciparum 20S proteasome core bound to a specific inhibitor
要素
試料: Plasmodium falciparum 20S proteasome core bound to a specific inhibitor
タンパク質・ペプチド: proteasome 20S core
リガンド: Mor-WLW vinyl sulphone (HET: 7F1)
-
超分子 #1000: Plasmodium falciparum 20S proteasome core bound to a specific inh...
超分子
名称: Plasmodium falciparum 20S proteasome core bound to a specific inhibitor タイプ: sample / ID: 1000 / Number unique components: 2
分子量
理論値: 760 KDa
-
分子 #1: proteasome 20S core
分子
名称: proteasome 20S core / タイプ: protein_or_peptide / ID: 1 詳細: The sample protein components are deposited in the PlasmoDB (the Plasmodium genome resource) 集合状態: dimer / 組換発現: No
詳細: 1.2/1.3 Quantifoil, 300 mesh Cu grids, coated with freshly floated thin layer of carbon
凍結
凍結剤: ETHANE / チャンバー内湿度: 95 % / 装置: FEI VITROBOT MARK III / 手法: blot 2.5 seconds before plunging
-
電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
詳細
Each exposure was recorded as 17 individual frames captured at a rate of 0.056 second/frame, each with an electron dose of 2.8 electrons/square angstrom. Data-set recorded using EPU software.
日付
2014年9月3日
撮影
カテゴリ: CCD フィルム・検出器のモデル: FEI FALCON II (4k x 4k) 実像数: 1816 / 平均電子線量: 48 e/Å2 / 詳細: each image was recorded as 17 frames
The particles were selected automatically using Relion, followed by manual inspection for the removal of false positives and addition of false negatives
CTF補正
詳細: full recorded image
最終 再構成
想定した対称性 - 点群: C2 (2回回転対称) / アルゴリズム: OTHER / 解像度のタイプ: BY AUTHOR / 解像度: 3.6 Å / 解像度の算出法: OTHER / ソフトウェア - 名称: Tigris, Spider, Imagic / 使用した粒子像数: 97720
The initial models of the Plasmodium falciparum 20S proteasome core subunits were obtained using the PHYRE 2 structure prediction server; model building was done using real space refinement in Coot and Phenix
精密化
空間: REAL / プロトコル: FLEXIBLE FIT
得られたモデル
PDB-5fmg: Structure and function based design of Plasmodium-selective proteasome inhibitors