1do7: Difference between revisions

Revision as of 14:04, 2 May 2008

CARBONMONOXY-MYOGLOBIN (MUTANT L29W) REBINDING STRUCTURE AFTER PHOTOLYSIS AT T< 180K

OverviewOverview

Myoglobin, a small globular haem protein that binds gaseous ligands such as O2, CO and NO reversibly at the haem iron, serves as a model for studying structural and dynamic aspects of protein reactions. Time-resolved spectroscopic measurements after photodissociation of the ligand revealed a complex ligand-binding reaction with multiple kinetic intermediates, resulting from protein relaxation and movements of the ligand within the protein. To observe the structural changes induced by ligand dissociation, we have carried out X-ray crystallographic investigations of carbon monoxy-myoglobin (MbCO mutant L29W) crystals illuminated below and above 180 K, complemented by time-resolved infrared spectroscopy of CO rebinding. Here we show that below 180 K photodissociated ligands migrate to specific sites within an internal cavity--the distal haem pocket--of an essentially immobilized, frozen protein, from where they subsequently rebind by thermally activated barrier crossing. Upon photodissociation above 180 K, ligands escape from the distal pocket, aided by protein fluctuations that transiently open exit channels. We recover most of the ligands in a cavity on the opposite side of the haem group.

About this StructureAbout this Structure

1DO7 is a Single protein structure of sequence from Physeter catodon. Full crystallographic information is available from OCA.

ReferenceReference

Ligand binding and conformational motions in myoglobin., Ostermann A, Waschipky R, Parak FG, Nienhaus GU, Nature. 2000 Mar 9;404(6774):205-8. PMID:10724176 Page seeded by OCA on Fri May 2 14:04:34 2008

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OCA

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 [[Image:1do7.jpg|left|200px]]
- {{Structure
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+The line below this paragraph, containing "STRUCTURE_1do7", creates the "Structure Box" on the page.
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+You may change the PDB parameter (which sets the PDB file loaded into the applet)
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-|GENE=
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-|RELATEDENTRY=[[1do1|1DO1]], [[1do3|1DO3]], [[1do4|1DO4]], [[1do7|1DO7]]
-|RESOURCES=<span class='plainlinks'>[http://oca.weizmann.ac.il/oca-docs/fgij/fg.htm?mol=1do7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1do7 OCA], [http://www.ebi.ac.uk/pdbsum/1do7 PDBsum], [http://www.rcsb.org/pdb/explore.do?structureId=1do7 RCSB]</span>
-}}
 '''CARBONMONOXY-MYOGLOBIN (MUTANT L29W) REBINDING STRUCTURE AFTER PHOTOLYSIS AT T< 180K'''
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 [[Category: Parak, F G.]]
 [[Category: Waschipky, R.]]
-[[Category: heme]]
+[[Category: Heme]]
-[[Category: ligand migration]]
+[[Category: Ligand migration]]
-[[Category: photolysed myoglobin]]
+[[Category: Photolysed myoglobin]]
-[[Category: respiratory protein]]
+[[Category: Respiratory protein]]
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May  2 14:04:34 2008''
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Sun Mar 30 19:45:23 2008''