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1hba
From Proteopedia
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[[Image:1hba.gif|left|200px]] | [[Image:1hba.gif|left|200px]] | ||
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'''HIGH-RESOLUTION X-RAY STUDY OF DEOXYHEMOGLOBIN ROTHSCHILD 37BETA TRP-> ARG: A MUTATION THAT CREATES AN INTERSUBUNIT CHLORIDE-BINDING SITE''' | '''HIGH-RESOLUTION X-RAY STUDY OF DEOXYHEMOGLOBIN ROTHSCHILD 37BETA TRP-> ARG: A MUTATION THAT CREATES AN INTERSUBUNIT CHLORIDE-BINDING SITE''' | ||
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[[Category: Arnone, A.]] | [[Category: Arnone, A.]] | ||
[[Category: Kavanaugh, J S.]] | [[Category: Kavanaugh, J S.]] | ||
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| - | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Fri May 2 18:39:52 2008'' | |
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Revision as of 15:39, 2 May 2008
HIGH-RESOLUTION X-RAY STUDY OF DEOXYHEMOGLOBIN ROTHSCHILD 37BETA TRP-> ARG: A MUTATION THAT CREATES AN INTERSUBUNIT CHLORIDE-BINDING SITE
Overview
The mutation site in hemoglobin Rothschild (37 beta Trp----Arg) is located in the "hinge region" of the alpha 1 beta 2 interface, a region that is critical for normal hemoglobin function. The mutation results in greatly reduced cooperativity and an oxygen affinity similar to that of hemoglobin A [Gacon, G., Belkhodja, O., Wajcman, H., & Labie, D. (1977) FEBS Lett. 82, 243-246]. Crystal were grown under "low-salt" conditions [100 mM Cl- in 10 mM phosphate buffer at pH 7.0 with poly(ethylene glycol) as a precipitating agent]. The crystal structure of deoxyhemoglobin Rothschild and the isomorphous crystal structure of deoxyhemoglobin A were refined at resolutions of 2.0 and 1.9 A, respectively. The mutation-induced structural changes were partitioned into components of (1) tetramer rotation, (2) quaternary structure rearrangement, and (3) deformations of tertiary structure. The quaternary change involves a 1 degree rotation of the alpha subunit about the "switch region" of the alpha 1 beta 2 interface. The tertiary changes are confined to residues at the alpha 1 beta 2 interface, with the largest shifts (approximately 0.4 A) located across the interface from the mutation site at the alpha subunit FG corner-G helix boundary. Most surprising was the identification of a mutation-generated anion-binding site in the alpha 1 beta 2 interface. Chloride binds at this site as a counterion for Arg 37 beta. The requirement of a counterion implies that the solution properties of hemoglobin Rothschild, in particular the dimer-tetramer equilibrium, should be very dependent upon the concentration and type of anions present.
About this Structure
1HBA is a Protein complex structure of sequences from Homo sapiens. Full crystallographic information is available from OCA.
Reference
High-resolution X-ray study of deoxyhemoglobin Rothschild 37 beta Trp----Arg: a mutation that creates an intersubunit chloride-binding site., Kavanaugh JS, Rogers PH, Case DA, Arnone A, Biochemistry. 1992 Apr 28;31(16):4111-21. PMID:1567857 Page seeded by OCA on Fri May 2 18:39:52 2008
