Biophysical Society Conference | Tahoe 2023

Proton Reactions: From Basic Science to Biomedical Applications

Monday Speaker Abstracts

KINETIC SELECTION IN TRANSPORTERS: TEASING OUT THE ROLES OF THE ELECTRICAL AND CHEMICAL GRADIENTS Jessica Swanson University of Utah, USA No Abstract

ELECTROCATALYTIC AND SPECTROSCOPIC STUDIES ON CYTOCHROME BD OXIDASE, A HIGHLY DIVERSE BACTERIAL MEMBRANE PROTEN Iryna Makarchuk 1 ; Jan Kägi 2 ; Frédéric Melin 1 ; Thorsten Friedrich 2 ; Petra Hellwig ; 1 University of Strasbourg, UMR 7140 , Strasbourg, France 2 University of Freiburg, Institute for Biochemistry, Freiburg im Breisgau, Germany The selective reduction of oxygen to water is crucial to life and a central process in aerobic organisms. It is catalyzed by several different enzymes, including cytochrome bd oxidases that are solely present in prokaryotes, including several pathogens. In addition, these enzymes play a crucial role in protection against oxidative stress, in virulence, adaptability and antibiotics resistance. The reduction of O 2 occurs at the high spin D-type heme in all cytochrome bd oxidases, that is also the binding site for several ligands from signaling processes, including NO, H 2 S and CO. Here we present the electrocatalytic study of the cytochrome bd I and bd II oxidases from Escherichia coli as well on other related bd oxidases. Structural parameters that are crucial for the reactivity towards oxygen are analyzed. The pH dependency of the binding and release of NO, an important signaling factor is presented. The influence of mutants in the proton channel on the NO release is discussed.

13