| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1942388 | Biochimica et Biophysica Acta (BBA) - Bioenergetics | 2012 | 5 Pages |
Most of the chlorophyll (Chl) cofactors in photosystem II (PSII) from Acaryochloris marina are Chld, although a few Chla molecules are also present. To evaluate the possibility that Chla may participate in the PD1/PD2 Chl pair in PSII from A. marina, the PD1•+/PD2•+ charge ratio was investigated using the PSII crystal structure analyzed at 1.9-Å resolution, while considering all possibilities for the Chld-containing PD1/PD2 pair, i.e., Chld/Chld, Chla/Chld, and Chld/Chla pairs. Chld/Chld and Chla/Chld pairs resulted in a large PD1•+ population relative to PD2•+, as identified in Chla/Chla homodimer pairs in PSII from other species, e.g., Thermosynechococcus elongatus PSII. However, the Chld/Chla pair possessed a PD1•+/PD2•+ ratio of approximately 50/50, which is in contrast to previous spectroscopic studies on A. marina PSII. The present results strongly exclude the possibility that the Chld/Chla pair serves as PD1/PD2 in A. marina PSII. This article is part of a Special Issue entitled: Photosynthesis Research for Sustainability: from Natural to Artificial.
► The PD1•+/PD2•+ charge ratio was investigated for the Chld-containing PD1/PD2 pair. ► Chld/Chld and Chla/Chld pairs resulted in a large PD1•+ population relative to PD2•+. ► However, the Chld/Chla pair possessed a PD1•+/PD2•+ ratio of approximately 50/50. ► The present results strongly exclude the possibility that the Chld/Chla pair serves as PD1/PD2 in Acaryochloris marina PSII.
