Ligation tunes protein reactivity in an ancient haemoglobin: Kinetic evidence for an allosteric mechanism in methanosarcina acetivorans protoglobin

Stefania Abbruzzetti, Lesley Tilleman, Stefano Bruno, Cristiano Viappiani, Filip Desmet, Sabine van Doorslaer, Massimo Coletta, Chiara Ciaccio, Paolo Ascenzi, Marco Nardini, Martino Bolognesi, Luc Moens, Sylvia Dewilde

Research output: Contribution to journalArticle

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.

Original languageEnglish
Article numbere33614
JournalPLoS One
Volume7
Issue number3
DOIs
Publication statusPublished - Mar 27 2012

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

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    Abbruzzetti, S., Tilleman, L., Bruno, S., Viappiani, C., Desmet, F., van Doorslaer, S., Coletta, M., Ciaccio, C., Ascenzi, P., Nardini, M., Bolognesi, M., Moens, L., & Dewilde, S. (2012). Ligation tunes protein reactivity in an ancient haemoglobin: Kinetic evidence for an allosteric mechanism in methanosarcina acetivorans protoglobin. PLoS One, 7(3), [e33614]. https://doi.org/10.1371/journal.pone.0033614