The structure of the diheme cytochrome c4 from Neisseria gonorrhoeae reveals multiple contributors to tuning reduction potentials

Copyright © 2024. Published by Elsevier Inc..

Cytochrome c4 (c4) is a diheme protein implicated as an electron donor to cbb3 oxidases in multiple pathogenic bacteria. Despite its prevalence, understanding of how specific structural features of c4 optimize its function is lacking. The human pathogen Neisseria gonorrhoeae (Ng) thrives in low oxygen environments owing to the activity of its cbb3 oxidase. Herein, we report characterization of Ng c4. Spectroelectrochemistry experiments of the wild-type (WT) protein have shown that the two Met/His-ligated hemes differ in potentials by ∼100 mV, and studies of the two His/His-ligated variants provided unambiguous assignment of heme A from the N-terminal domain of the protein as the high-potential heme. The crystal structure of the WT protein at 2.45 Å resolution has revealed that the two hemes differ in their solvent accessibility. In particular, interactions made by residues His57 and Ser59 in Loop1 near the axial ligand Met63 contribute to the tight enclosure of heme A, working together with the surface charge, to raise the reduction potential of the heme iron in this domain. The structure reveals a prominent positively-charged patch, which encompasses surfaces of both domains. In contrast to prior findings with c4 from Pseudomonas stutzeri, the interdomain interface of Ng c4 contributes minimally to the values of the heme iron potentials in the two domains. Analyses of the heme solvent accessibility, interface properties, and surface charges offer insights into the interplay of these structural elements in tuning redox properties of c4 and other multiheme proteins.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:253

Enthalten in:

Journal of inorganic biochemistry - 253(2024) vom: 26. Apr., Seite 112496

Sprache:

Englisch

Beteiligte Personen:

Zhong, Fangfang [VerfasserIn]
Reik, Morgan E [VerfasserIn]
Ragusa, Michael J [VerfasserIn]
Pletneva, Ekaterina V [VerfasserIn]

Links:

Volltext

Themen:

42VZT0U6YR
9007-43-6
Cytochromes c
Diheme cytochrome c
E1UOL152H7
EC 1.-
EC 1.8.2.-
Electron transfer
Heme
Heme proteins
Interdomain interface
Iron
Journal Article
Oxidoreductases
Reduction potentials
Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.
Solvents

Anmerkungen:

Date Completed 23.02.2024

Date Revised 26.04.2024

published: Print-Electronic

Citation Status MEDLINE

doi:

10.1016/j.jinorgbio.2024.112496

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM36820166X