4NK2

Crystal structure of Hell's gate globin IV

4NK2 の概要

• エントリーDOI: 10.2210/pdb4nk2/pdb
• 分子名称: Hemoglobin-like protein, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• 機能のキーワード: truncated, hemoglobins, heme, truncated hemoglobin, oxygen binding
• 由来する生物種: Methylacidiphilum infernorum
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 46639.64

構造登録者

Jamil, F. (登録日: 2013-11-12, 公開日: 2014-09-24, 最終更新日: 2023-09-20)

主引用文献

Jamil, F.,Teh, A.H.,Schadich, E.,Saito, J.A.,Najimudin, N.,Alam, M.
Crystal structure of truncated haemoglobin from an extremely thermophilic and acidophilic bacterium.
J.Biochem., 156:97-106, 2014

PubMed Abstract: A truncated haemoglobin (tHb) has been identified in an acidophilic and thermophilic methanotroph Methylacidiphilium infernorum. Hell's Gate Globin IV (HGbIV) and its related tHbs differ from all other bacterial tHbs due to their distinctively large sequence and polar distal haem pocket residues. Here we report the crystal structure of HGbIV determined at 1.96 Å resolution. The HGbIV structure has the distinctive 2/2 α-helical structure with extensions at both termini. It has a large distal site cavity in the haem pocket surrounded by four polar residues: His70(B9), His71(B10), Ser97(E11) and Trp137(G8). This cavity can bind bulky ligands such as a phosphate ion. Conformational shifts of His71(B10), Leu90(E4) and Leu93(E7) can also provide more space to accommodate larger ligands than the phosphate ion. The entrance/exit of such bulky ligands might be facilitated by positional flexibility in the CD1 loop, E helix and haem-propionate A. Therefore, the large cavity in HGbIV with polar His70(B9) and His71(B10), in contrast to the distal sites of other bacterial tHbs surrounded by non-polar residues, suggests its distinct physiological functions.

PubMed: 24733432
DOI: 10.1093/jb/mvu023

実験手法

X-RAY DIFFRACTION (1.96 Å)