View source for 1gzx

[[Image:1gzx.gif|left|200px]]<br /><applet load="1gzx" size="350" color="white" frame="true" align="right" spinBox="true" 
caption="1gzx, resolution 2.1&Aring;" />
'''OXY T STATE HAEMOGLOBIN: OXYGEN BOUND AT ALL FOUR HAEMS'''<br />

==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 &lt;==&gt; 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.

==Disease==
Known diseases associated with this structure: Erythremias, alpha- OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141800 141800]], Erythremias, beta- OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141900 141900]], Erythrocytosis OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141850 141850]], HPFH, deletion type OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141900 141900]], Heinz body anemia OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141850 141850]], Heinz body anemias, alpha- OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141800 141800]], Heinz body anemias, beta- OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141900 141900]], Hemoglobin H disease OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141850 141850]], Hypochromic microcytic anemia OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141850 141850]], Methemoglobinemias, alpha- OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141800 141800]], Methemoglobinemias, beta- OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141900 141900]], Sickle cell anemia OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141900 141900]], Thalassemia, alpha- OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141850 141850]], Thalassemia-beta, dominant inclusion-body OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141900 141900]], Thalassemias, alpha- OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141800 141800]], Thalassemias, beta- OMIM:[[http://www.ncbi.nlm.nih.gov/entrez/dispomim.cgi?id=141900 141900]]

==About this Structure==
1GZX is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens] with <scene name='pdbligand=HEM:'>HEM</scene> and <scene name='pdbligand=OXY:'>OXY</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Known structural/functional Site: <scene name='pdbsite=HB1:O2+Binding+Site+For+Chain+D'>HB1</scene>. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1GZX 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:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=8642597 8642597]
[[Category: Homo sapiens]]
[[Category: Protein complex]]
[[Category: Dodson, G.]]
[[Category: Liddington, R.]]
[[Category: Paoli, M.]]
[[Category: Tame, J.]]
[[Category: Wilkinson, A.]]
[[Category: HEM]]
[[Category: OXY]]
[[Category: cooperativity]]
[[Category: haem protein]]
[[Category: oxygen binding]]
[[Category: transport]]

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Feb  3 09:44:34 2008''