1S69

The X-ray structure of the cyanobacteria Synechocystis hemoglobin "cyanoglobin" with cyanide ligand

Summary for 1S69

• Entry DOI: 10.2210/pdb1s69/pdb
• Related: 1S6A
• Descriptor: Cyanoglobin, CITRATE ANION, CYANIDE ION, ... (5 entities in total)
• Functional Keywords: 2 on 2 helical fold, globin, heme, iron, hemoglobin, cyanobacteria, oxygen binding, hexacoordinate, truncated, oxygen storage-transport complex, oxygen storage/transport
• Biological source: Synechocystis sp.
• Total number of polymer chains: 1
• Total formula weight: 14720.23

Authors

Trent III, J.T.,Kundu, S.,Hoy, J.A.,Hargrove, M.S. (deposition date: 2004-01-22, release date: 2004-09-21, Last modification date: 2024-11-13)

Primary citation

Trent III, J.T.,Kundu, S.,Hoy, J.A.,Hargrove, M.S.
Crystallographic analysis of synechocystis cyanoglobin reveals the structural changes accompanying ligand binding in a hexacoordinate hemoglobin.
J.Mol.Biol., 341:1097-1108, 2004

PubMed Abstract: The crystal structures of cyanide and azide-bound forms of the truncated hemoglobin from Synechocystis are presented at 1.8 angstroms resolution. A comparison with the structure of the endogenously liganded protein reveals a conformational shift unprecedented in hemoglobins, and provides the first picture of a hexacoordinate hemoglobin in both the bis-histidyl and the exogenously coordinated states. The structural changes between the different conformations are confined to two regions of the protein; the B helix, and the E helix, including the EF loop. A molecular "hinge" controlling movement of the E helix is observed in the EF loop, which is composed of three principal structural elements: Arg64, the heme-d-propionate, and a three-residue extension of the F helix. Additional features of the structural transition between the two protein conformations are discussed as they relate to the complex ligand-binding behavior observed in hexacoordinate hemoglobins, and the potential physiological function of this class of proteins.

PubMed: 15289104
DOI: 10.1016/j.jmb.2004.05.070

Experimental method

X-RAY DIFFRACTION (1.68 Å)