Detection of anion‐linked polymerization of the tetrameric hemoglobin from Scapharca inaequivalvis by 31Cl NMR spectroscopy

FEBS Letters

Drakenberg, Torbjo¨rn²  Forse´n, Sture²  Chiancone, Emilia¹ 

[1] CNR Center of Molecular Biology, Department of Biochemical Sciences, University ‘La Sapienza’, 00185 Rome, Italy;Physical Chemistry 2, Chemical Centre, Lund University, PO Box 124, S-221 00 Lund, Sweden

关键词: Hemoglobin;    Polymerization;    35CL-NMR;    (Scapharca);   

DOI  :  10.1016/0014-5793(88)80466-6

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Ion binding to the hemoglobin components of Scapharca inaequivalvis has been measured directly in quadrupole relaxation experiments of ²³Na and ³⁵Cl. The dimeric and tetrameric hemoglobins interact weakly with sodium ions, but differ in their interaction with chloride ions. The dimeric hemoglobin binds chloride ions with low affinity, whereas the tetrameric protein has high-affinity chloride binding sites. Binding of chloride ions to these high-affinity sites brings about an oxygen-linked polymerization which manifests itself in an unusual dependence of the ³⁵Cl excess linewidth on the concentration of the anion. Polymerization is more pronounced in the deoxygenated than in the oxygenated derivative: in the former, it has been observed previously in sedimentation velocity experiments. The sensitivity of the ³⁵Cl excess linewidth on polymer formation indicates that the residence time of the transiently bound chloride on the tetrameric hemoglobin is not shorter than the correlation time of the molecule (2 × 10⁻¹ s⁻¹).

【 授权许可】

Unknown