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Updated: Apr 12, 2026

Purification of Active Photosystem I-Light Harvesting Complex I from Plant Tissues
Published on: February 3, 2023
Directionality of electron transfer in cyanobacterial photosystem I at 298 and 77K
Hiroki Makita1, Gary Hastings1
1Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, USA.
Abstract:
Electron transfer processes in cyanobacterial photosystem I particles from Synechocystis sp. PCC 6803 with a high potential naphthoquinone (2,3-dichloro-1,4-naphthoquinone) incorporated into the A1 binding site have been studied at 298 and 77K using time-resolved visible and infrared difference spectroscopy. The high potential naphthoquinone inhibits electron transfer past A1, and biphasic P700(+)A1(-) radical pair recombination is observed. The two phases are assigned to P700(+)A1B(-) and P700(+)A1A(-) recombination. Analyses of the transient absorption changes indicate that the ratio of A- and B-branch electron transfer is 95:5 at 77 K and 77:23 at 298 K.
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