Kinetics of phyllosemiquinone oxidation in the Photosystem I reaction centre of Acaryochloris marina

► The oxidation kinetics of secondary intermediates in PS I of A. marina are biphasic. ► The decay is characterised by lifetimes of 88 ± 6 ns and 345 ± 10 ns. ► Both these lifetimes are slower than in typical Chl a-binding PS I reaction centres. ► Possible mechanism of electron transfer is discussed.