1gzx
From Proteopedia
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'''OXY T STATE HAEMOGLOBIN: OXYGEN BOUND AT ALL FOUR HAEMS''' | '''OXY T STATE HAEMOGLOBIN: OXYGEN BOUND AT ALL FOUR HAEMS''' | ||
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[[Category: Tame, J.]] | [[Category: Tame, J.]] | ||
[[Category: Wilkinson, A.]] | [[Category: Wilkinson, A.]] | ||
| - | [[Category: | + | [[Category: Cooperativity]] |
| - | [[Category: | + | [[Category: Haem protein]] |
| - | [[Category: | + | [[Category: Oxygen binding]] |
| - | [[Category: | + | [[Category: Transport]] |
| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 18:14:04 2008'' | |
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | |
Revision as of 15:14, 2 May 2008
OXY T STATE HAEMOGLOBIN: OXYGEN BOUND AT ALL FOUR HAEMS
Overview
The cooperative binding of oxygen by haemoglobin results from restraints on ligand binding in the T state. The unfavourable interactions made by the ligands at the haems destabilise the T state and favour the high affinity R state. The T <==> R equilibrium leads, in the presence of a ligand, to a rapid increase in the R state population and therefore generates cooperative binding. There is now considerable understanding of this phenomenon, but the interactions that reduce ligand affinity in the T state have not yet been fully explored, owing to the difficulties in preparing T state haemoglobin crystals in which all the subunits are oxygenated. A protocol has been developed to oxygenate deoxy T state adult human haemoglobin (HbA) crystals in air at 4 C at all four haems without significant loss of crystalline order. The X-ray crystal structure, determined to 2.1 A spacing, shows significant changes in the alpha and beta haem pockets as well as changes at the alpha(1)beta(2) interface in the direction of the R quaternary structure. Most of the shifts and deviations from deoxy T state HbA are similar to, but larger than, those previously observed in the T state met and other partially liganded T state forms. They provide clear evidence of haem-haem interaction in the T state.
About this Structure
1GZX is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
Crystal structure of T state haemoglobin with oxygen bound at all four haems., Paoli M, Liddington R, Tame J, Wilkinson A, Dodson G, J Mol Biol. 1996 Mar 8;256(4):775-92. PMID:8642597 Page seeded by OCA on Fri May 2 18:14:04 2008
