Understanding mechanisms in cooperative proteins requires the analysis of the intermediate ligation states. The release of hydrogen ions at the intermediate states of native and chemically modified hemoglobin, known as the Bohr effect, is an indicator of the protein tertiary/quaternary transitions, useful for testing models of cooperativity. The Bohr effects due to ligation of one subunit of a dimer and two subunits across the dimer interface are not additive. The reductions of the Bohr effect due to the chemical modification of a Bohr group of one and two alpha or beta subunits are additive. The Bohr effects of monoliganded chemically modified hemoglobins indicate the additivity of the effects of ligation and chemical modification with the possible exception of ligation and chemical modification of the alpha subunits. These observations suggest that ligation of a subunit brings about a tertiary structure change of hemoglobin in the T quaternary structure, which breaks some salt bridges, releases hydrogen ions, and is signaled across the dimer interface in such a way that ligation of a second subunit in the adjacent dimer promotes the switch from the T to the R quaternary structure. The rupture of the salt bridges per se does not drive the transition.

The Bohr effect of hemoglobin intermediates and the role of salt bridges in the tertiary/quaternary transitions / R. Russo, L. Benazzi, M. Perrella. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 276:17(2001 Apr 27), pp. 13628-13634.

The Bohr effect of hemoglobin intermediates and the role of salt bridges in the tertiary/quaternary transitions

R. Russo
Primo
;
M. Perrella
Ultimo
2001

Abstract

Understanding mechanisms in cooperative proteins requires the analysis of the intermediate ligation states. The release of hydrogen ions at the intermediate states of native and chemically modified hemoglobin, known as the Bohr effect, is an indicator of the protein tertiary/quaternary transitions, useful for testing models of cooperativity. The Bohr effects due to ligation of one subunit of a dimer and two subunits across the dimer interface are not additive. The reductions of the Bohr effect due to the chemical modification of a Bohr group of one and two alpha or beta subunits are additive. The Bohr effects of monoliganded chemically modified hemoglobins indicate the additivity of the effects of ligation and chemical modification with the possible exception of ligation and chemical modification of the alpha subunits. These observations suggest that ligation of a subunit brings about a tertiary structure change of hemoglobin in the T quaternary structure, which breaks some salt bridges, releases hydrogen ions, and is signaled across the dimer interface in such a way that ligation of a second subunit in the adjacent dimer promotes the switch from the T to the R quaternary structure. The rupture of the salt bridges per se does not drive the transition.
English
Settore BIO/11 - Biologia Molecolare
Articolo
Sì, ma tipo non specificato
27-apr-2001
American Society for Biochemistry and Molecular Biology
276
17
13628
13634
Periodico con rilevanza internazionale
http://www.jbc.org/cgi/content/full/276/17/13628
info:eu-repo/semantics/article
The Bohr effect of hemoglobin intermediates and the role of salt bridges in the tertiary/quaternary transitions / R. Russo, L. Benazzi, M. Perrella. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - 276:17(2001 Apr 27), pp. 13628-13634.
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Prodotti della ricerca::01 - Articolo su periodico
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262
Article (author)
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R. Russo, L. Benazzi, M. Perrella
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/28426
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