Catalytic Activity and Proton Translocation of Reconstituted Respiratory Complex i Monitored by Surface-Enhanced Infrared Absorption Spectroscopy

Oscar Gutiérrez-Sanz, Enrico Forbrig, Ana P. Batista, Manuela M. Pereira, Johannes Salewski, Maria A. Mroginski, Robert Götz, Antonio L. De Lacey, Jacek Kozuch, Ingo Zebger

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4 Citations (Scopus)

Abstract

Respiratory complex I (CpI) is a key player in the way organisms obtain energy, being an energy transducer, which couples nicotinamide adenine dinucleotide (NADH)/quinone oxidoreduction with proton translocation by a mechanism that remains elusive so far. In this work, we monitored the function of CpI in a biomimetic, supported lipid membrane system assembled on a 4-aminothiophenol (4-ATP) self-assembled monolayer by surface-enhanced infrared absorption spectroscopy. 4-ATP serves not only as a linker molecule to a nanostructured gold surface but also as pH sensor, as indicated by concomitant density functional theory calculations. In this way, we were able to monitor NADH/quinone oxidoreduction-induced transmembrane proton translocation via the protonation state of 4-ATP, depending on the net orientation of CpI molecules induced by two complementary approaches. An associated change of the amide I/amide II band intensity ratio indicates conformational modifications upon catalysis which may involve movements of transmembrane helices or other secondary structural elements, as suggested in the literature [ Di Luca et al., Proc. Natl. Acad. Sci. U.S.A., 2017, 114, E6314-E6321.

Original languageEnglish
Pages (from-to)5703-5711
Number of pages9
JournalLangmuir
Volume34
Issue number20
DOIs
Publication statusPublished - 22 May 2018

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