1s6a | pdb_00001s6a
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| 1s6a, resolution 1.69Å | |||||||||||||
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| Ligands: | FLC, AZI and HEM | ||||||||||||
| Gene: | GLBN, SLR2097 (Synechocystis sp.) | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
The X-ray structure of the cyanobacteria Synechocystis hemoglobin "cyanoglobin" with azide ligand
Overview
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.
About this Structure
1S6A is a Single protein structure of sequence from Synechocystis sp.. Full crystallographic information is available from OCA.
Reference
Crystallographic analysis of synechocystis cyanoglobin reveals the structural changes accompanying ligand binding in a hexacoordinate hemoglobin., Trent JT 3rd, Kundu S, Hoy JA, Hargrove MS, J Mol Biol. 2004 Aug 20;341(4):1097-108. PMID:15289104
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