Biochemical and spectroscopic characterization of dinuclear Mn-sites in artificial four-helix bundle proteins

Tien L. Olson, Eduardo Espiritu, Selvakumar Edwardraja, Elizabeth Canarie, Marco Flores, Joann Williams, Giovanna Ghirlanda, James Allen

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

To better understand metalloproteins with Mn-clusters, we have designed artificial four-helix bundles to have one, two, or three dinuclear metal centers able to bind Mn(II). Circular dichroism measurements showed that the Mn-proteins have substantial α-helix content, and analysis of electron paramagnetic resonance spectra is consistent with the designed number of bound Mn-clusters. The Mn-proteins were shown to catalyze the conversion of hydrogen peroxide into molecular oxygen. The loss of hydrogen peroxide was dependent upon the concentration of protein with bound Mn, with the proteins containing multiple Mn-clusters showing greater activity. Using an oxygen sensor, the oxygen concentration was found to increase with a rate up to 0.4 μM/min, which was dependent upon the concentrations of hydrogen peroxide and the Mn-protein. In addition, the Mn-proteins were shown to serve as electron donors to bacterial reaction centers using optical spectroscopy. Similar binding of the Mn-proteins to reaction centers was observed with an average dissociation constant of 2.3 μM. The Mn-proteins with three metal centers were more effective at this electron transfer reaction than the Mn-proteins with one or two metal centers. Thus, multiple Mn-clusters can be incorporated into four-helix bundles with the capability of performing catalysis and electron transfer to a natural protein.

Original languageEnglish (US)
Pages (from-to)945-954
Number of pages10
JournalBiochimica et Biophysica Acta - Bioenergetics
Volume1858
Issue number12
DOIs
StatePublished - Dec 1 2017

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Proteins
Hydrogen Peroxide
Metals
Electrons
Oxygen
Metalloproteins
Oxygen sensors
Electron Spin Resonance Spectroscopy
Molecular oxygen
Circular Dichroism
Catalysis
Spectrum Analysis
Carrier Proteins
Paramagnetic resonance

Keywords

  • Catalase
  • De novo design
  • Electron transfer
  • Metalloproteins
  • Photosynthesis

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Cell Biology

Cite this

Biochemical and spectroscopic characterization of dinuclear Mn-sites in artificial four-helix bundle proteins. / Olson, Tien L.; Espiritu, Eduardo; Edwardraja, Selvakumar; Canarie, Elizabeth; Flores, Marco; Williams, Joann; Ghirlanda, Giovanna; Allen, James.

In: Biochimica et Biophysica Acta - Bioenergetics, Vol. 1858, No. 12, 01.12.2017, p. 945-954.

Research output: Contribution to journalArticle

Olson, Tien L. ; Espiritu, Eduardo ; Edwardraja, Selvakumar ; Canarie, Elizabeth ; Flores, Marco ; Williams, Joann ; Ghirlanda, Giovanna ; Allen, James. / Biochemical and spectroscopic characterization of dinuclear Mn-sites in artificial four-helix bundle proteins. In: Biochimica et Biophysica Acta - Bioenergetics. 2017 ; Vol. 1858, No. 12. pp. 945-954.
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