2r4z: Difference between revisions

Revision as of 19:44, 21 February 2008

Ligand Migration and Binding in The Dimeric Hemoglobin of Scapharca Inaequivalvis: Structure of I25W with CO

OverviewOverview

Using Fourier transform infrared (FTIR) spectroscopy combined with temperature derivative spectroscopy (TDS) at cryogenic temperatures, we have studied CO binding to the heme and CO migration among cavities in the interior of the dimeric hemoglobin of Scapharca inaequivalvis (HbI) after photodissociation. By combining these studies with X-ray crystallography, three transient ligand docking sites were identified: a primary docking site B in close vicinity to the heme iron, and two secondary docking sites C and D corresponding to the Xe4 and Xe2 cavities of myoglobin. To assess the relevance of these findings for physiological binding, we also performed flash photolysis experiments on HbICO at room temperature and equilibrium binding studies with dioxygen. Our results show that the Xe4 and Xe2 cavities serve as transient docking sites for unbound ligands in the protein, but not as way stations on the entry/exit pathway. For HbI, the so-called histidine gate mechanism proposed for other globins appears as a plausible entry/exit route as well.

About this StructureAbout this Structure

2R4Z is a Single protein structure of sequence from Scapharca inaequivalvis with , and as ligands. Full crystallographic information is available from OCA.

ReferenceReference

Ligand migration and binding in the dimeric hemoglobin of Scapharca inaequivalvis., Nienhaus K, Knapp JE, Palladino P, Royer WE Jr, Nienhaus GU, Biochemistry. 2007 Dec 11;46(49):14018-31. Epub 2007 Nov 15. PMID:18001141

Page seeded by OCA on Thu Feb 21 18:44:52 2008

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OCA

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 ==Overview==
-Using Fourier transform infrared (FTIR) spectroscopy combined with, temperature derivative spectroscopy (TDS) at cryogenic temperatures, we, have studied CO binding to the heme and CO migration among cavities in the, interior of the dimeric hemoglobin of Scapharca inaequivalvis (HbI) after, photodissociation. By combining these studies with X-ray crystallography, three transient ligand docking sites were identified: a primary docking, site B in close vicinity to the heme iron, and two secondary docking sites, C and D corresponding to the Xe4 and Xe2 cavities of myoglobin. To assess, the relevance of these findings for physiological binding, we also, performed flash photolysis experiments on HbICO at room temperature and, equilibrium binding studies with dioxygen. Our results show that the Xe4, and Xe2 cavities serve as transient docking sites for unbound ligands in, the protein, but not as way stations on the entry/exit pathway. For HbI, the so-called histidine gate mechanism proposed for other globins appears, as a plausible entry/exit route as well.
+Using Fourier transform infrared (FTIR) spectroscopy combined with temperature derivative spectroscopy (TDS) at cryogenic temperatures, we have studied CO binding to the heme and CO migration among cavities in the interior of the dimeric hemoglobin of Scapharca inaequivalvis (HbI) after photodissociation. By combining these studies with X-ray crystallography, three transient ligand docking sites were identified: a primary docking site B in close vicinity to the heme iron, and two secondary docking sites C and D corresponding to the Xe4 and Xe2 cavities of myoglobin. To assess the relevance of these findings for physiological binding, we also performed flash photolysis experiments on HbICO at room temperature and equilibrium binding studies with dioxygen. Our results show that the Xe4 and Xe2 cavities serve as transient docking sites for unbound ligands in the protein, but not as way stations on the entry/exit pathway. For HbI, the so-called histidine gate mechanism proposed for other globins appears as a plausible entry/exit route as well.
 ==About this Structure==
@@ Line 10: / Line 10: @@
 ==Reference==
-Ligand Migration and Binding in the Dimeric Hemoglobin of Scapharca inaequivalvis(,)., Nienhaus K, Knapp JE, Palladino P, Royer WE Jr, Nienhaus GU, Biochemistry. 2007 Nov 15;. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18001141 18001141]
+Ligand migration and binding in the dimeric hemoglobin of Scapharca inaequivalvis., Nienhaus K, Knapp JE, Palladino P, Royer WE Jr, Nienhaus GU, Biochemistry. 2007 Dec 11;46(49):14018-31. Epub 2007 Nov 15. PMID:[http://ispc.weizmann.ac.il//pmbin/getpm?pmid=18001141 18001141]
 [[Category: Scapharca inaequivalvis]]
 [[Category: Single protein]]
-[[Category: Jr., W.E.Royer.]]
+[[Category: Jr., W E.Royer.]]
-[[Category: Knapp, J.E.]]
+[[Category: Knapp, J E.]]
-[[Category: Nienhaus, G.U.]]
+[[Category: Nienhaus, G U.]]
 [[Category: Nienhaus, K.]]
 [[Category: Palladino, P.]]
@@ Line 31: / Line 31: @@
 [[Category: oxygen transport]]
-''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Wed Jan 23 11:31:57 2008''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 18:44:52 2008''