ジャーナル: IUCrJ / 年: 2019 タイトル: Cryo-EM reveals the asymmetric assembly of squid hemocyanin. 著者: Yoshikazu Tanaka / Sanae Kato / Markus Stabrin / Stefan Raunser / Takashi Matsui / Christos Gatsogiannis / 要旨: The oxygen transporter of molluscs, hemocyanin, consists of long pearl-necklace-like subunits of several globular domains. The subunits assemble in a complex manner to form cylindrical decamers. ...The oxygen transporter of molluscs, hemocyanin, consists of long pearl-necklace-like subunits of several globular domains. The subunits assemble in a complex manner to form cylindrical decamers. Typically, the first six domains of each subunit assemble together to form the cylinder wall, while the C-terminal domains form a collar that fills or caps the cylinder. During evolution, various molluscs have been able to fine-tune their oxygen binding by deleting or adding C-terminal domains and adjusting their inner-collar architecture. However, squids have duplicated one of the wall domains of their subunits instead. Here, using cryo-EM and an optimized refinement protocol implemented in , this work tackled the symmetry-mismatched structure of squid hemocyanin, revealing the precise effect of this duplication on its quaternary structure and providing a potential model for its structural evolution.
名称: Squid Hemocyanin / タイプ: COMPLEX 詳細: TpH is a decamer of a 400 kDa subunit. Each subunit is composed by 8 paralogous O2 binding functional units (A,B,C,D,D*,E,F,G). The ten subunits of TpH acquire 4 different overall conformations. Entity ID: all / 由来: NATURAL
分子量
値: 3.8 MDa / 実験値: NO
由来(天然)
生物種: Todarodes pacificus (イカ)
緩衝液
pH: 7.5
緩衝液成分
ID
濃度
名称
式
Buffer-ID
1
100mM
HEPES
1
2
200mM
calciumchloride
CaCl2
1
試料
濃度: 2.9 mg/ml / 包埋: NO / シャドウイング: NO / 染色: NO / 凍結: YES
試料支持
グリッドの材料: COPPER / グリッドのタイプ: Quantifoil R2/1
急速凍結
装置: GATAN CRYOPLUNGE 3 / 凍結剤: ETHANE
-
電子顕微鏡撮影
実験機器
モデル: Titan Krios / 画像提供: FEI Company
顕微鏡
モデル: FEI TITAN KRIOS
電子銃
電子線源: FIELD EMISSION GUN / 加速電圧: 300 kV / 照射モード: OTHER
電子レンズ
モード: BRIGHT FIELDBright-field microscopy / Cs: 0 mm