9FBK

Diheme cytochrome c Kustd1711 from Kuenenia stuttgartiensis, without glycerol cryoprotectant

Summary for 9FBK

• Entry DOI: 10.2210/pdb9fbk/pdb
• Related: 7zs0 7zs1 7zs2
• Descriptor: Hypothetical (Diheme) protein, CALCIUM ION, HEME C, ... (4 entities in total)
• Functional Keywords: heme c, anaerobic ammonium oxidation, electron transport
• Biological source: Candidatus Kuenenia
• Total number of polymer chains: 1
• Total formula weight: 35732.56

Authors

Hauser, D.,Barends, T.R.M. (deposition date: 2024-05-14, release date: 2024-12-25, Last modification date: 2025-02-05)

Primary citation

Akram, M.,Hauser, D.,Dietl, A.,Steigleder, M.,Ullmann, G.M.,Barends, T.R.M.
Redox potential tuning by calcium ions in a novel c-type cytochrome from an anammox organism.
J.Biol.Chem., 301:108082-108082, 2024

PubMed 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 mV 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.

PubMed: 39675707
DOI: 10.1016/j.jbc.2024.108082

Experimental method

X-RAY DIFFRACTION (1.7 Å)