Protoglobin from Methanosarcina acetivorans (MaPgb) is a dimeric globin with peculiar structural properties such as a completely buried haem and two orthogonal tunnels connecting the distal cavity to the solvent. CO binding to and dissociation from MaPgb occur through a biphasic kinetics. We show that the heterogenous kinetics arises from binding to (and dissociation from) two tertiary conformations in ligation-dependent equilibrium. Ligation favours the species with high binding rate (and low dissociation rate). The equilibrium is shifted towards the species with low binding (and high dissociation) rates for the unliganded molecules. A quantitative model is proposed to describe the observed carbonylation kinetics.

Ligation tunes protein reactivity in an ancient haemoglobin : kinetic evidence for an allosteric mechanism in Methanosarcina acetivorans protoglobin / S. Abbruzzetti, L. Tilleman, S. Bruno, C. Viappiani, F. Desmet, S. Van Doorslaer, M. Coletta, C. Ciaccio, P. Ascenzi, M. Nardini, M. Bolognesi, L. Moens, S. Dewilde. - In: PLOS ONE. - ISSN 1932-6203. - 7:3(2012 Mar 27), pp. e33614.1-e33614.12. [10.1371/journal.pone.0033614]

Ligation tunes protein reactivity in an ancient haemoglobin : kinetic evidence for an allosteric mechanism in Methanosarcina acetivorans protoglobin

M. Nardini;M. Bolognesi;
2012

Abstract

Protoglobin from Methanosarcina acetivorans (MaPgb) is a dimeric globin with peculiar structural properties such as a completely buried haem and two orthogonal tunnels connecting the distal cavity to the solvent. CO binding to and dissociation from MaPgb occur through a biphasic kinetics. We show that the heterogenous kinetics arises from binding to (and dissociation from) two tertiary conformations in ligation-dependent equilibrium. Ligation favours the species with high binding rate (and low dissociation rate). The equilibrium is shifted towards the species with low binding (and high dissociation) rates for the unliganded molecules. A quantitative model is proposed to describe the observed carbonylation kinetics.
Allosteric Regulation ; Archaeal Proteins ; Carbon Monoxide ; Ferrous Compounds ; Globins ; Hemoglobins ; Kinetics ; Methanosarcina ; Photolysis ; Protein Binding ; Protein Multimerization ; Recombinant Proteins
Settore BIO/10 - Biochimica
27-mar-2012
Article (author)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/223747
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