2grh | pdb_00002grh
M37V mutant of Scapharca dimeric hemoglobin, with CO bound
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| 2grh, resolution 1.50Å | |||||||||||||
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| Ligands: | CMO, HEM | ||||||||||||
| Gene: | HBI (Scapharca inaequivalvis) | ||||||||||||
| Related: | 3SDH, 2GRF, 2GRZ
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| Resources: | FirstGlance, OCA, PDBsum, RCSB | ||||||||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||||||||
Overview
Protein allostery provides mechanisms for regulation of biological function at the molecular level. We present here an investigation of global, ligand-induced allosteric transition in a protein by time-resolved x-ray diffraction. The study provides a view of structural changes in single crystals of Scapharca dimeric hemoglobin as they proceed in real time, from 5 ns to 80 micros after ligand photodissociation. A tertiary intermediate structure forms rapidly (<5 ns) as the protein responds to the presence of an unliganded heme within each R-state protein subunit, with key structural changes observed in the heme groups, neighboring residues, and interface water molecules. This intermediate lays a foundation for the concerted tertiary and quaternary structural changes that occur on a microsecond time scale and are associated with the transition to a low-affinity T-state structure. Reversal of these changes shows a considerable lag as a T-like structure persists well after ligand rebinding, suggesting a slow T-to-R transition.
About this Structure
2GRH is a Single protein structure of sequence from Scapharca inaequivalvis. Full crystallographic information is available from OCA.
Reference
Allosteric action in real time: time-resolved crystallographic studies of a cooperative dimeric hemoglobin., Knapp JE, Pahl R, Srajer V, Royer WE Jr, Proc Natl Acad Sci U S A. 2006 May 16;103(20):7649-54. Epub 2006 May 9. PMID:16684887
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