1BAB

HEMOGLOBIN THIONVILLE: AN ALPHA-CHAIN VARIANT WITH A SUBSTITUTION OF A GLUTAMATE FOR VALINE AT NA-1 AND HAVING AN ACETYLATED METHIONINE NH2 TERMINUS

Summary for 1BAB

• Entry DOI: 10.2210/pdb1bab/pdb
• Descriptor: HEMOGLOBIN THIONVILLE (DEOXY) (ALPHA CHAIN), HEMOGLOBIN THIONVILLE (DEOXY) (BETA CHAIN), PROTOPORPHYRIN IX CONTAINING FE, ... (5 entities in total)
• Functional Keywords: oxygen transport
• Biological source: Homo sapiens (human); More
• Total number of polymer chains: 4
• Total formula weight: 65113.61

Authors

Kavanaugh, J.S.,Arnone, A. (deposition date: 1992-05-06, release date: 1994-01-31, Last modification date: 2024-11-13)

Primary citation

Vasseur, C.,Blouquit, Y.,Kister, J.,Prome, D.,Kavanaugh, J.S.,Rogers, P.H.,Guillemin, C.,Arnone, A.,Galacteros, F.,Poyart, C.,Rosa, J.,Wajcman, H.
Hemoglobin Thionville. An alpha-chain variant with a substitution of a glutamate for valine at NA-1 and having an acetylated methionine NH2 terminus.
J.Biol.Chem., 267:12682-12691, 1992

PubMed Abstract: In hemoglobin (Hb) Thionville, the substitution of a glutamic acid for the alpha-chain NH2-terminal valine inhibits the cleavage of the initiator methionine which is then acetylated. The elongation of the alpha-chain NH2 terminus modifies the three-dimensional structure of hemoglobin at a region that is known to have an important role in the allosteric regulation of oxygen binding. Relative to Hb A, Hb Thionville has a lower affinity for oxygen, and the heterotropic allosteric effects of protons, chloride, and bezafibrate are reduced. In contrast, the response to 2,3-diphosphoglycerate is normal. Analysis of oxygen equilibrium data within the framework of the two-state allosteric model indicates that the structure of deoxy Hb Thionville is stabilized relative to that of deoxy Hb A. The x-ray crystal structure of deoxy Hb Thionville shows that the glutamate side chain extends away from the alpha 1-alpha 2 interface, whereas the methionine side chain (which has two conformations) extends into the alpha 1-alpha 2 interface, physically displacing chloride and bezafibrate. The increased stability of deoxy Hb Thionville is due to new intrasubunit and intersubunit contacts made by the methionine. These interactions replace the indirect contacts, made through bound chloride ions, that Val-1 alpha normally contributes to the alpha 1-alpha 2 interface.

PubMed: 1618774

Experimental method

X-RAY DIFFRACTION (1.5 Å)