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1J7S

Crystal Structure of deoxy HbalphaYQ, a mutant of HbA

Summary for 1J7S
Entry DOI10.2210/pdb1j7s/pdb
Related1J7W 1J7Y 1QI8
DescriptorHemoglobin, PROTOPORPHYRIN IX CONTAINING FE, ... (4 entities in total)
Functional Keywordsglobin, oxygen storage-transport complex, oxygen storage/transport
Biological sourceHomo sapiens (human)
More
Total number of polymer chains4
Total formula weight64755.31
Authors
Miele, A.E.,Draghi, F.,Arcovito, A.,Bellelli, A.,Brunori, M.,Travaglini-Allocatelli, C.,Vallone, B. (deposition date: 2001-05-18, release date: 2002-02-27, Last modification date: 2024-02-07)
Primary citationMiele, A.E.,Draghi, F.,Arcovito, A.,Bellelli, A.,Brunori, M.,Travaglini-Allocatelli, C.,Vallone, B.
Control of heme reactivity by diffusion: structural basis and functional characterization in hemoglobin mutants.
Biochemistry, 40:14449-14458, 2001
Cited by
PubMed Abstract: The effect of mutagenesis on O(2), CO, and NO binding to mutants of human hemoglobin, designed to modify some features of the reactivity that hinder use of hemoglobin solutions as blood substitute, has been extensively investigated. The kinetics may be interpreted in the framework of the Monod-Wyman-Changeux two-state allosteric model, based on the high-resolution crystallographic structures of the mutants and taking into account the control of heme reactivity by the distal side mutations. The mutations involve residues at topological position B10 and E7, i.e., Leu (B10) to Tyr and His (E7) to Gln, on either the alpha chains alone (yielding the hybrid tetramer Hbalpha(YQ)), the beta chains alone (hybrid tetramer Hbbeta(YQ)), or both types of chains (Hb(YQ)). Our data indicate that the two mutations affect ligand diffusion into the pocket, leading to proteins with low affinity for O(2) and CO, and especially with reduced reactivity toward NO, a difficult goal to achieve. The observed kinetic heterogeneity between the alpha(YQ) and beta(YQ) chains in Hb(YQ) has been rationalized on the basis of the three-dimensional structure of the active site. Furthermore, we report for the first time an experiment of partial CO binding, selective for the beta chains, to high salt crystals of the mutant Hb(YQ) in the T-state; these crystallographic data may be interpreted as "snapshots" of the initial events possibly occurring on ligand binding to the T-allosteric state of this peculiar mutant Hb.
PubMed: 11724557
DOI: 10.1021/bi011602d
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (2.2 Å)
Structure validation

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