7VLD

Oxy-deoxy intermediate of V2 hemoglobin at 69% oxygen saturation

7VLD の概要

• エントリーDOI: 10.2210/pdb7vld/pdb
• 分子名称: Extracellular A1 globin, Extracellular A2 globin, Extracellular B2 globin, ... (9 entities in total)
• 機能のキーワード: allostery, structural transition, giant hemoglobin, oxygen transport
• 由来する生物種: Lamellibrachia satsuma (Hydrothermal vent tubeworm); 詳細
• タンパク質・核酸の鎖数: 8
• 化学式量合計: 136140.31

構造登録者

Numoto, N.,Onoda, S.,Kawano, Y.,Okumura, H.,Baba, S.,Fukumori, Y.,Miki, K.,Ito, N. (登録日: 2021-10-02, 公開日: 2022-05-18, 最終更新日: 2024-10-23)

主引用文献

Numoto, N.,Onoda, S.,Kawano, Y.,Okumura, H.,Baba, S.,Fukumori, Y.,Miki, K.,Ito, N.
Structures of oxygen dissociation intermediates of 400 kDa V2 hemoglobin provide coarse snapshots of the protein allostery.
Biophys Physicobio., 19:1-10, 2022

PubMed Abstract: Ever since the historic discovery of the cooperative oxygenation of its multiple subunits, hemoglobin (Hb) has been among the most exhaustively studied allosteric proteins. However, the lack of structural information on the intermediates between oxygenated and deoxygenated forms prevents our detailed understanding of the molecular mechanism of its allostery. It has been difficult to prepare crystals of intact oxy-deoxy intermediates and to individually identify the oxygen saturation for each subunit. However, our recent crystallographic studies have demonstrated that giant Hbs from annelids are suitable for overcoming these problems and can provide abundant information on oxy-deoxy intermediate structures. Here, we report the crystal structures of oxy-deoxy intermediates of a 400 kDa Hb (V2Hb) from the annelid , following up on a series of previous studies of similar giant Hbs. Four intermediate structures had average oxygen saturations of 78%, 69%, 55%, and 26%, as determined by the occupancy refinement of the bound oxygen based on ambient temperature factors. The structures demonstrate that the cooperative oxygen dissociation is weaker, large ternary and quaternary changes are induced at a later stage of the oxygen dissociation process, and the ternary and quaternary changes are smaller with local perturbations. Nonetheless, the overall structural transition seemed to proceed in the manner of the MWC two-state model. Our crystallographic snapshots of the allosteric transition of V2Hb provide important experimental evidence for a more detailed understanding of the allostery of Hbs by extension of the Monod-Wyman-Changeux (MWC) model.

PubMed: 35797404
DOI: 10.2142/biophysico.bppb-v19.0019

実験手法

X-RAY DIFFRACTION (2.1 Å)