This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
1la6
From Proteopedia
| |||||||
| , resolution 2.0Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | , and | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
The crystal structure of Trematomus newnesi hemoglobin in a partial hemichrome state
Overview
Tetrameric hemoglobins are the most widely used systems in studying protein cooperativity. Allosteric effects in hemoglobins arise from the switch between a relaxed (R) state and a tense (T) state occurring upon oxygen release. Here we report the 2.0-A crystal structure of the main hemoglobin component of the Antarctic fish Trematomus newnesi, in a partial hemichrome form. The two alpha-subunit iron atoms are bound to a CO molecule, whereas in the beta subunits the distal histidine residue is the sixth ligand of the heme iron. This structure, a tetrameric hemoglobin in the hemichrome state, demonstrates that the iron coordination by the distal histidine, usually associated with denaturing states, may be tolerated in a native-like hemoglobin structure. In addition, several features of the tertiary and quaternary organization of this structure are intermediate between the R and T states and agree well with the R --> T transition state properties obtained by spectroscopic and kinetic techniques. The analysis of this structure provides a detailed pathway of heme-heme communication and it indicates that the plasticity of the beta heme pocket plays a role in the R --> T transition of tetrameric hemoglobins.
About this Structure
1LA6 is a Protein complex structure of sequences from Trematomus newnesi. Full crystallographic information is available from OCA.
Reference
The crystal structure of a tetrameric hemoglobin in a partial hemichrome state., Riccio A, Vitagliano L, di Prisco G, Zagari A, Mazzarella L, Proc Natl Acad Sci U S A. 2002 Jul 23;99(15):9801-6. Epub 2002 Jul 1. PMID:12093902
Page seeded by OCA on Thu Mar 20 12:28:26 2008
