Work

Redox potential tuning by calcium ions in a novel c-type cytochrome from an anammox organism

Year: 2024

Type: article

Abstract: The electrochemical potentials of redox-active proteins need to be tuned accurately to the correct values for proper biological function. Here, we describe a diheme cytochrome c with high heme redox potentials of about +350 mV, despite having a large overall negative charge, which typically reduces redox potentials. High-resolution crystal structures, spectroelectrochemical measurements, and high-end computational methods show how this is achieved: each heme iron has a calcium cation positioned next to it at a distance of only 6.9 Å, raising their redox potentials by several hundred millivolts through electrostatic interaction. We suggest that this has evolved to provide the protein with a high redox potential despite its large negative surface charge, which it likely requires for interactions with redox partners.

Source: Journal of Biological Chemistry

DOI: 10.1016/j.jbc.2024.108082

Authors: Mohd. Akram, David Hauser, Andreas Dietl, Matthias Steigleder, G. Matthias Ullmann, Thomas R.M. Barends

Institutions: Max Planck Institute for Medical Research, University of Bayreuth

Language: English

Topic: Metalloenzymes and iron-sulfur proteins

Subfield: Renewable Energy, Sustainability and the Environment

Field: Energy

Domain: Physical Sciences

Open Access status: gold

Estimated APC paid: $2,800

Funders: Deutsche Forschungsgemeinschaft, European Synchrotron Radiation Facility, Radboud Universiteit, Max-Planck-Gesellschaft