title: Circular dichroism spectroscopy of tertiary and quaternary conformations of human hemoglobin entrapped in wet silica gels.
abstract: 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.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Parma, Italy.
authors.forename: Luca
authors.initials: L
authors.lastname: Ronda
authors.forename: Stefano
authors.initials: S
authors.lastname: Bruno
authors.forename: Cristiano
authors.initials: C
authors.lastname: Viappiani
authors.forename: Stefania
authors.initials: S
authors.lastname: Abbruzzetti
authors.forename: Andrea
authors.initials: A
authors.lastname: Mozzarelli
authors.forename: Kenneth C
authors.initials: KC
authors.lastname: Lowe
authors.forename: Stefano
authors.initials: S
authors.lastname: Bettati
mesh_terms: D002263:Carboxyhemoglobin / Q000737:chemistry; D002942:Circular Dichroism; D006454:Hemoglobins / Q000737:chemistry*; D006801:Humans; D007700:Kinetics; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary; D058428:Silica Gel; D012822:Silicon Dioxide
chemical_list: D006454:Hemoglobins; D058428:Silica Gel; D012822:Silicon Dioxide; C100003:deoxyhemoglobin; D002263:Carboxyhemoglobin