Cryo-EM structure of Bimetallic dodecameric cage design 3 (BMC3) from cytochrome cb562
マップデータ
2.6 A map of dodecameric cage
試料
複合体: Bimetallic dodecameric cage 3 (BMC3)
タンパク質・ペプチド: Soluble cytochrome b562
リガンド: HEME C
リガンド: ACETOHYDROXAMIC ACID
リガンド: ZINC ION
リガンド: FE (III) ION
リガンド: water
機能・相同性
Cytochrome b562 / Cytochrome b562 / Cytochrome c/b562 / electron transport chain / periplasmic space / electron transfer activity / iron ion binding / heme binding / Soluble cytochrome b562
ジャーナル: Nature / 年: 2020 タイトル: Constructing protein polyhedra via orthogonal chemical interactions. 著者: Eyal Golub / Rohit H Subramanian / Julian Esselborn / Robert G Alberstein / Jake B Bailey / Jerika A Chiong / Xiaodong Yan / Timothy Booth / Timothy S Baker / F Akif Tezcan / 要旨: Many proteins exist naturally as symmetrical homooligomers or homopolymers. The emergent structural and functional properties of such protein assemblies have inspired extensive efforts in ...Many proteins exist naturally as symmetrical homooligomers or homopolymers. The emergent structural and functional properties of such protein assemblies have inspired extensive efforts in biomolecular design. As synthesized by ribosomes, proteins are inherently asymmetric. Thus, they must acquire multiple surface patches that selectively associate to generate the different symmetry elements needed to form higher-order architectures-a daunting task for protein design. Here we address this problem using an inorganic chemical approach, whereby multiple modes of protein-protein interactions and symmetry are simultaneously achieved by selective, 'one-pot' coordination of soft and hard metal ions. We show that a monomeric protein (protomer) appropriately modified with biologically inspired hydroxamate groups and zinc-binding motifs assembles through concurrent Fe and Zn coordination into discrete dodecameric and hexameric cages. Our cages closely resemble natural polyhedral protein architectures and are, to our knowledge, unique among designed systems in that they possess tightly packed shells devoid of large apertures. At the same time, they can assemble and disassemble in response to diverse stimuli, owing to their heterobimetallic construction on minimal interprotein-bonding footprints. With stoichiometries ranging from [2 Fe:9 Zn:6 protomers] to [8 Fe:21 Zn:12 protomers], these protein cages represent some of the compositionally most complex protein assemblies-or inorganic coordination complexes-obtained by design.
モデル: Quantifoil R1.2/1.3 / 材質: COPPER / メッシュ: 400 / 前処理 - タイプ: GLOW DISCHARGE / 前処理 - 雰囲気: AIR / 前処理 - 気圧: 101.325 kPa / 詳細: The grid was glow discharged at 20 mA for 30 s.
凍結
凍結剤: ETHANE / 装置: FEI VITROBOT MARK IV
詳細
Protein solutions containing 20 micromolar BMC3 in 20 mM Tris (pH 8.5) were incubated with [FeSO4] = 20 micromolar, [ZnCl2] = 60 micromolar for 2-3 h to form cages. Samples were concentrated 10 fold prior to grid preparation.
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電子顕微鏡法
顕微鏡
FEI TITAN KRIOS
撮影
フィルム・検出器のモデル: GATAN K2 SUMMIT (4k x 4k) 実像数: 4672 / 平均露光時間: 10.0 sec. / 平均電子線量: 60.0 e/Å2
Symmetry mates were generated from the atomic model to build the dodecameric cage. Chain IDs were re-assigned to ascend from A-L. The cage PDB was manually fit to the EM density map in UCSF Chimera and refined using phenix.real_space_refine
精密化
空間: REAL / プロトコル: RIGID BODY FIT
得られたモデル
PDB-6ovh: Cryo-EM structure of Bimetallic dodecameric cage design 3 (BMC3) from cytochrome cb562