Journal Article

A megacomplex composed of both photosystem reaction centres in higher plants

Akimoto, S., Tanaka, A., Yokono, M., Takabayashi, A.

2015

Overview

Throughout the history of oxygen evolution, two types of photosystem reaction centres (PSI and PSII) have worked in a coordinated manner. The oxygen evolving centre is an integral part of PSII, and extracts an electron from water. PSI accepts the electron, and accumulates reducing power. Traditionally, PSI and PSII are thought to be spatially dispersed. Here, we show that about half of PSIIs are physically connected to PSIs in Arabidopsis thaliana . In the PSI–PSII complex, excitation energy is transferred efficiently between the two closely interacting reaction centres. PSII diverts excitation energy to PSI when PSII becomes closed-state in the PSI–PSII complex. The formation of PSI–PSII complexes is regulated by light conditions. Quenching of excess energy by PSI might be one of the physiological functions of PSI–PSII complexes. Plants have two types of photosystem reaction centres, PSI and PSII, that are traditionally thought to be spatially separate. Here, Yokono et al . show in Arabidopsis that around half of PSII physically interacts with PSI to efficiently transfer excitation energy between the complexes, and this interaction is regulated by light.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 140/125 / 631/1647/334/2244/710 / 631/449/1734 / 631/57 / 82/1 / 82/29 / 82/58 / Arabidopsis / Arabidopsis Proteins - physiology / Electron Transport / Energy Transfer / Humanities and Social Sciences / Light / multidisciplinary / Oxygen - metabolism / Photosystem I Protein Complex - physiology / Photosystem II Protein Complex - physiology / Science / Science (multidisciplinary)