TY - JOUR
T1 - Proton-Coupled Electron Transfer of Plastoquinone Redox Reactions in Photosystem II
T2 - A Pump-Probe Ultraviolet Resonance Raman Study
AU - Chen, Jun
AU - Chen, Jinfan
AU - Liu, Ying
AU - Zheng, Yang
AU - Zhu, Qingjun
AU - Han, Guangye
AU - Shen, Jian Ren
N1 - Funding Information:
This work was supported by National Natural Science Foundation of China (21573223, 11705170, and 31470339) and Foundation from Institute of Materials CAEP (TP01201603, TP02201709).
Publisher Copyright:
© 2019 American Chemical Society.
PY - 2019/6/20
Y1 - 2019/6/20
N2 - Plastoquinones (PQs) act as electron and proton mediators in photosystem II (PSII) for solar-to-chemical energy conversion. It is known that the redox potential of PQ varies in a wide range spanning hundreds of millivolts; however, its structural origin is not known yet. Here, by developing a pump-probe ultraviolet resonance Raman technique, we measured the vibrational structures of PQs including QA and QB in cyanobacterial PSII directly. The conversion of QA to QA•- in the Mn-depleted PSII is verified by direct observation of the distinct QA•- vibrational bands. A frequency upshift of the ring C=O/C=C stretch band at 1565 cm-1 for QA•- was observed, which suggests a π-πinteraction between the quinone ring and Trp253. In contrast, proton-coupled reduction of QA to QAH upon light-driven electron transfer is demonstrated in PSII without QB bound. The H-bond between QA and His214 is likely the proton origin of this proton-coupled electron transfer.
AB - Plastoquinones (PQs) act as electron and proton mediators in photosystem II (PSII) for solar-to-chemical energy conversion. It is known that the redox potential of PQ varies in a wide range spanning hundreds of millivolts; however, its structural origin is not known yet. Here, by developing a pump-probe ultraviolet resonance Raman technique, we measured the vibrational structures of PQs including QA and QB in cyanobacterial PSII directly. The conversion of QA to QA•- in the Mn-depleted PSII is verified by direct observation of the distinct QA•- vibrational bands. A frequency upshift of the ring C=O/C=C stretch band at 1565 cm-1 for QA•- was observed, which suggests a π-πinteraction between the quinone ring and Trp253. In contrast, proton-coupled reduction of QA to QAH upon light-driven electron transfer is demonstrated in PSII without QB bound. The H-bond between QA and His214 is likely the proton origin of this proton-coupled electron transfer.
UR - http://www.scopus.com/inward/record.url?scp=85067004508&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85067004508&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.9b00959
DO - 10.1021/acs.jpclett.9b00959
M3 - Article
C2 - 31117681
AN - SCOPUS:85067004508
SN - 1948-7185
VL - 10
SP - 3240
EP - 3247
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 12
ER -