Issue 14, 2016

Comparative kinetic and energetic modelling of phyllosemiquinone oxidation in Photosystem I

Abstract

The oxidation kinetics of phyllo(semi)quinone (PhQ), which acts as an electron transfer (ET) intermediate in the Photosystem I reaction centre, are described by a minimum of two exponential phases, characterised by lifetimes in the 10–30 ns and 150–300 ns ranges. The fastest phase is considered to be dominated by the oxidation of the PhQ molecule coordinated by the PsaB reaction centre subunit (PhQB), and the slowest phase is dominated by the oxidation of the PsaA coordinated PhQ (PhQA). Testing different energetic schemes within a unified theory-based kinetic modelling approach provides reliable limit-values for some of the physical–chemical parameters controlling these ET reactions: (i) the value of ΔG0 associated with PhQA oxidation is smaller than ∼+30 meV; (ii) the value of the total reorganisation energy (λt) likely exceeds 0.7 eV; (iii) different mean nuclear modes are coupled to PhQB and PhQA oxidation, the former being larger, and both being ≥100 cm−1.

Graphical abstract: Comparative kinetic and energetic modelling of phyllosemiquinone oxidation in Photosystem I

Supplementary files

Article information

Article type
Paper
Submitted
29 Oct 2015
Accepted
01 Mar 2016
First published
02 Mar 2016

Phys. Chem. Chem. Phys., 2016,18, 9687-9701

Author version available

Comparative kinetic and energetic modelling of phyllosemiquinone oxidation in Photosystem I

S. Santabarbara and G. Zucchelli, Phys. Chem. Chem. Phys., 2016, 18, 9687 DOI: 10.1039/C5CP06590A

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements