3AG0

Crystal structure of carbonmonoxy human cytoglobin

3AG0 の概要

• エントリーDOI: 10.2210/pdb3ag0/pdb
• 関連するPDBエントリー: 1v5h 2DC3
• 分子名称: Cytoglobin, PROTOPORPHYRIN IX CONTAINING FE, CARBON MONOXIDE, ... (4 entities in total)
• 機能のキーワード: globins, heme, carbon monoxide, complex, ligands, hexacoordination, bis-his, disulfide bond, iron, metal-binding, oxygen transport, transport
• 由来する生物種: Homo sapiens (human)
• 細胞内の位置: Cytoplasm (By similarity): Q8WWM9
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 22222.24

構造登録者

Makino, M.,Sawai, H.,Shiro, Y.,Sugimoto, H. (登録日: 2010-03-17, 公開日: 2011-02-02, 最終更新日: 2023-11-08)

主引用文献

Makino, M.,Sawai, H.,Shiro, Y.,Sugimoto, H.
Crystal structure of the carbon monoxide complex of human cytoglobin
Proteins, 79:1143-1153, 2011

PubMed Abstract: Cytoglobin (Cgb) is a vertebrate heme-containing globin-protein expressed in a broad range of mammalian tissues. Unlike myoglobin, Cgb displays a hexa-coordinated (bis-hystidyl) heme iron atom, having the heme distal His81(E7) residue as the endogenous sixth ligand. In the present study, we crystallized human Cgb in the presence of a reductant Na₂S₂O₄ under a carbon monoxide (CO) atmosphere, and determined the crystal structure at 2.6 A resolution. The CO ligand occupies the sixth axial position of the heme ferrous iron. Eventually, the imidazole group of His81(E7) is expelled from the sixth position and swings out of the distal heme pocket. The flipping motion of the His81 imidazole group accompanies structural readjustments of some residues (Gln62, Phe63, Gln72, and Ser75) in both the CD-corner and D-helix regions of Cgb. On the other hand, no significant structural changes were observed in other Cgb regions, for example, on the proximal side. These structural alterations that occurred as a result of exogenous ligand (CO) binding are clearly different from those observed in other vertebrate hexa-coordinated globins (mouse neuroglobin, Drosophila melanogaster hemoglobin) and penta-coordinated sperm whale myoglobin. The present study provides the structural basis for further discussion of the unique ligand-binding properties of Cgb.

PubMed: 21254233
DOI: 10.1002/prot.22950

実験手法

X-RAY DIFFRACTION (2.6 Å)