1JS8

Structure of a Functional Unit from Octopus Hemocyanin

1JS8 の概要

• エントリーDOI: 10.2210/pdb1js8/pdb
• 分子名称: Hemocyanin, alpha-D-mannopyranose-(1-3)-[alpha-D-mannopyranose-(1-6)]alpha-D-mannopyranose-(1-6)-[beta-D-mannopyranose-(1-3)]beta-D-mannopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-alpha-D-glucopyranose, 2-acetamido-2-deoxy-beta-D-glucopyranose-(1-4)-2-acetamido-2-deoxy-beta-D-glucopyranose, ... (7 entities in total)
• 機能のキーワード: glycoprotein, mollusc, oxygen-transport, thioether bond, oxygen storage-transport complex, oxygen storage/transport
• 由来する生物種: Octopus dofleini
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 92282.41

構造登録者

Cuff, M.E.,Miller, K.I.,van Holde, K.E.,Hendrickson, W.A. (登録日: 2001-08-16, 公開日: 2001-10-03, 最終更新日: 2024-10-09)

主引用文献

Cuff, M.E.,Miller, K.I.,van Holde, K.E.,Hendrickson, W.A.
Crystal structure of a functional unit from Octopus hemocyanin.
J.Mol.Biol., 278:855-870, 1998

PubMed Abstract: Hemocyanins are giant oxygen transport proteins found in many arthropods and molluscs. Freely dissolved in the hemolymph, they are multisubunit proteins that contain many copies of the active site, a copper atom pair that reversibly binds oxygen. Octopus hemocyanin is composed of ten subunits, each of which contain seven oxygen-binding "functional units". The carboxyl-terminal 47 kDa functional unit, Odg, is a proteolytic isolate that binds oxygen reversibly while exhibiting slight Bohr and magnesium ion effects. In this work we present the X-ray structure determination and analysis of Odg at 2.3 A resolution. Odg has two structural domains: a largely alpha-helical copper binding domain, and a five-stranded anti-parallel beta-sandwich with the jelly roll topology found in many viruses. Six histidine residues ligate the copper atoms, one of which is involved in a thioether bridge. The results show that the hemocyanin from the mollusc and that from the arthropod have distinct tertiary folds in addition to the long recognized differences in their quaternary structures. Nonetheless, a comparison of Octopus and horseshoe crab hemocyanin reveals a similar active site, in a striking example of perhaps both convergent and divergent evolution.

PubMed: 9614947
DOI: 10.1006/jmbi.1998.1647

実験手法

X-RAY DIFFRACTION (2.3 Å)