Chloride facilitates Mn(III) formation during photoassembly of the Photosystem II oxygen-evolving complex
Journal Article
·
· Photosynthesis Research
- Louisiana State University, Baton Rouge, LA (United States); Louisiana State University
- Louisiana State University, Baton Rouge, LA (United States)
The Mn4Ca oxygen-evolving complex (OEC) in Photosystem II (PSII) is assembled in situ from free Mn2+, Ca2+, and water. In an early light-driven step, Mn2+ in a protein high-affinity site is oxidized to Mn3+. Using dual-mode electron paramagnetic resonance spectroscopy, we observed that Mn3+ accumulation increases as chloride concentration increases in spinach PSII membranes depleted of all extrinsic subunits. At physiologically relevant pH values, this effect requires the presence of calcium. Here, when combined with pH studies, we conclude that the first Mn2+ oxidation event in OEC assembly requires a deprotonation that is facilitated by chloride.
- Research Organization:
- Louisiana State University, Baton Rouge, LA (United States)
- Sponsoring Organization:
- USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB); Herman Frasch Fund for Chemical Research
- Grant/Contract Number:
- SC0020119
- OSTI ID:
- 2283330
- Alternate ID(s):
- OSTI ID: 1909567
- Journal Information:
- Photosynthesis Research, Journal Name: Photosynthesis Research Journal Issue: 3 Vol. 152; ISSN 0166-8595
- Publisher:
- SpringerCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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