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Circular dichroism spectroscopy of tertiary and quaternary conformations of human hemoglobin entrapped in wet silica gels
Author(s) -
Ronda Luca,
Bruno Stefano,
Viappiani Cristiano,
Abbruzzetti Stefania,
Mozzarelli Andrea,
Lowe Kenneth C.,
Bettati Stefano
Publication year - 2006
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1110/ps.062272306
Subject(s) - circular dichroism , spectroscopy , protein quaternary structure , quaternary , chemistry , hemoglobin , crystallography , vibrational circular dichroism , materials science , organic chemistry , geology , biochemistry , physics , paleontology , protein subunit , gene , quantum mechanics
The relative contributions to changes in visible and near UV circular dichroism spectra of hemoglobin of heme ligation and tertiary and quaternary conformational transitions were separated by exploiting the slowing down of structural relaxations for proteins encapsulated in wet, nanoporous silica gels. Spectral signatures, previously assumed to be characteristic of T and R quaternary states, were demonstrated to be specific to different tertiary conformations. The results support the view that ligation and allosteric effectors can modulate the structural and functional properties of hemoglobin by regulating the equilibrium between the same tertiary species within both quaternary states.