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Updated: May 26, 2026

T-wave Ion Mobility-mass Spectrometry: Basic Experimental Procedures for Protein Complex Analysis
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Symmetry distortion in the human hemoglobin tetramer induced by asymmetric ligation

Naoya Shibayama1

  • 1Department of Physiology, Division of Biophysics, Jichi Medical University, 3311-1 Yakushiji, Shimotsuke, Tochigi 329-0498, Japan. shibayam@jichi.ac.jp

FEBS Letters
|December 7, 2011
PubMed

To investigate the conformational changes in human tetrameric (αβ)(2) hemoglobin upon binding of the first two ligands, we have measured the kinetics of reactions between 4,4'-dithiodipyridine and β93Cys sulfhydryl groups of four diliganded hemoglobins by using CO-bound Fe(II)-Ni(II) hybrids with and without β-β cross-linking. The data show that all the diliganded intermediates have high sulfhydryl reactivities, which are greater than or equal to that for the fully-liganded end state, especially when containing liganded α subunit(s). The results also reveal that both the asymmetrically (α1β1 and α1β2) diliganded species show similar high rates of sulfhydryl reactivity and biphasic kinetics, suggesting a new conformation but only slight functional distortion caused by asymmetric ligation.

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