Research Lab

Biochemistry and Bioenergetics of Heme Proteins

Biochemistry and Bioenergetics of Heme Proteins
Research Interests

The research team uses complementary biochemical and biophysical methods to study the respiratory chain of electrogenic bacteria, which couple their oxidative metabolism to the reduction of extracellular electron acceptors such as toxic/radioactive metals or electrode surfaces. The structural and functional characterization of key electron transfer components, particularly multiheme cytochromes and bacterial conductive filaments, permits the elucidation of the bacteria’s respiratory pathways and endows their rational engineering for optimization of Geobacter-based biotechnological (bioremediation, microbial electrosynthesis, bioenergy) and bioelectronic applications.

Research Highlights
Exploring electron transfer proteins of electrogenic bacteria for sustainable biotechnological applications


The electrogenic bacterium Geobacter sulfurreducens transfers electrons to the cell’s exterior and produces electricity in microbial fuel cells. The outer membrane cytochrome c OmcF is involved in this respiratory pathway. The molecular bases for the modulation of OmcF’s redox behaviour were determined. Measurements of electron production and electron flux rates revealed
that the bacterial electron flow is regulated by increasing the reduced/oxidized ratios of the cytochromes in response to a decrease of the oxidative activity of the extracellular metals. The electron flow is independent of the concentration and type of oxidant and results in ATP homeostasis.


highlight 2020


Representative Projects

  • “Wired life: Exploring the unprecedented electron transfer paths revealed by bacterial electrically conductive filaments for bioenergy and bioelectronics applications“, FCT-MCTES, Total: €231,083, Carlos Salgueiro (PI)
  • “Redox Maze: Elucidation of bacterial extracellular electron transfer pathways for sustainable bio-based applications“, FCT-MCTES, Total: €49,900, Leonor Morgado (PI), Carlos Salgueiro (Co-PI)
  • “Look out over the wall: rational powering of microbial nanowires for sustainable bioenergy-based applications”, FCT-MCTES, Total and Unit funding: €220,459, Carlos Salgueiro (PI).

Selected Publications

Antunes, JMA; Silva, MA; Salgueiro, CA; Morgado, L. 2022. Electron Flow From the Inner Membrane Towards the Cell Exterior in Geobacter sulfurreducens: Biochemical Characterization of Cytochrome CbcL. Frontiers in Microbiology, 13, DOI: 10.3389/fmicb.2022.898015
Karamash, M; Stumpe, M; Dengjel, J; Salgueiro, CA; Giese, B; Fromm, KM. 2022. Reduction Kinetic of Water Soluble Metal Salts by Geobacter sulfurreducens: Fe2+/Hemes Stabilize and Regulate Electron Flux Rates. Frontiers in Microbiology, 13, DOI: 10.3389/fmicb.2022.909109
Paquete, CM; Morgado, L; Salgueiro, CA; Louro, RO. 2022. Molecular Mechanisms of Microbial Extracellular Electron Transfer: The Importance of Multiheme Cytochromes. Frontiers in Bioscience-Landmark, 27, DOI: 10.31083/j.fbl2706174
Ferreira, MR; Fernandes, TM; Turner, DL; Salgueiro, CA. 2022. Molecular geometries of the heme axial ligands from the triheme cytochrome PpcF from Geobacter metallireducens reveal a conserved heme core architecture. ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS, 723, DOI: 10.1016/
Salgueiro, CA; Morgado, L; Silva, MA; Ferreira, MR; Fernandes, TM; Portela, PC. 2022. From iron to bacterial electroconductive filaments: Exploring cytochrome diversity using Geobacter bacteria. COORDINATION CHEMISTRY REVIEWS, 452, DOI: 10.1016/j.ccr.2021.214284
Morgado, L; Salgueiro, CA. 2022. Elucidation of complex respiratory chains: a straightforward strategy to monitor electron transfer between cytochromes. Metallomics, 14, DOI: 10.1093/mtomcs/mfac012
Tomás MFernandes; Leonor Morgado; David Turner; Carlos ASalgueiro. 2021. Protein Engineering of Electron Transfer Components from Electroactive <i>Geobacter</i> Bacteria. ANTIOXIDANTS, DOI: 10.3390/antiox10060844
Silva, MA; Portela, PC; Salgueiro, CA. 2021. Rational design of electron/proton transfer mechanisms in the exoelectrogenic bacteria Geobacter sulfurreducens. BIOCHEMICAL JOURNAL, 478, DOI: 10.1042/BCJ20210365
Portela, PC; Silva, MA; Teixeira, LR; Salgueiro, CA. 2021. A unique aromatic residue modulates the redox range of a periplasmic multiheme cytochrome from Geobacter metallireducens. JOURNAL OF BIOLOGICAL CHEMISTRY, 296, DOI: 10.1016/j.jbc.2021.100711
Fernandes, TM; Folgosa, F; Teixeira, M; Salgueiro, CA; Morgado, L. 2021. Structural and functional insights of GSU0105, a unique multiheme cytochrome from G. sulfurreducens. BIOPHYSICAL JOURNAL, 120, DOI: 10.1016/j.bpj.2021.10.023