NDLI: Mechanism of proton-coupled quinone reduction in Photosystem II

Content Provider	PubMed Central
Author	Saito, Keisuke Rutherford, A. William Hiroshi, Ishikita
Abstract	Photosystem II uses light to drive water oxidation and plastoquinone (PQ) reduction. PQ reduction involves two PQ cofactors, QA and QB, working in series. QA is a one-electron carrier, whereas QB undergoes sequential reduction and protonation to form QBH2. QBH2 exchanges with PQ from the pool in the membrane. Based on the atomic coordinates of the Photosystem II crystal structure, we analyzed the proton transfer (PT) energetics adopting a quantum mechanical/molecular mechanical approach. The potential-energy profile suggests that the initial PT to QB •– occurs from the protonated, D1-His252 to QB • – via D1-Ser264. The second PT is likely to occur from D1-His215 to QBH− via an H-bond with an energy profile with a single well, resulting in the formation of QBH2 and the D1-His215 anion. The pathway for reprotonation of D1-His215– may involve bicarbonate, D1-Tyr246 and water in the QB site. Formate ligation to Fe2+ did not significantly affect the protonation of reduced QB, suggesting that formate inhibits QBH2 release rather than its formation. The presence of carbonate rather than bicarbonate seems unlikely because the calculations showed that this greatly perturbed the potential of the nonheme iron, stabilizing the Fe3+ state in the presence of QB •–, a situation not encountered experimentally. H-bonding from D1-Tyr246 and D2-Tyr244 to the bicarbonate ligand of the nonheme iron contributes to the stability of the semiquinones. A detailed mechanistic model for QB reduction is presented.
Related Links	http://dx.doi.org/10.1073/pnas.1212957110
Ending Page	959
Page Count	6
Starting Page	954
File Format	PDF
ISSN	10916490
e-ISSN	10916490
Journal	Proceedings of the National Academy of Sciences of the United States of America
Issue Number	3
Volume Number	110
Language	English
Publisher	National Academy of Sciences
Publisher Date	2013-01-15
Access Restriction	Open
Rights Holder	National Academy of Sciences
Subject Keyword	Research in Higher Education
Content Type	Text
Resource Type	Article
Subject	Multidisciplinary

Sl.	Authority	Responsibilities	Communication Details
1	Ministry of Education (GoI), Department of Higher Education	Sanctioning Authority	https://www.education.gov.in/ict-initiatives
2	Indian Institute of Technology Kharagpur	Host Institute of the Project: The host institute of the project is responsible for providing infrastructure support and hosting the project	https://www.iitkgp.ac.in
3	National Digital Library of India Office, Indian Institute of Technology Kharagpur	The administrative and infrastructural headquarters of the project	Dr. B. Sutradhar bsutra@ndl.gov.in
4	Project PI / Joint PI	Principal Investigator and Joint Principal Investigators of the project	Dr. B. Sutradhar bsutra@ndl.gov.in Prof. Saswat Chakrabarti will be added soon
5	Website/Portal (Helpdesk)	Queries regarding NDLI and its services	support@ndl.gov.in
6	Contents and Copyright Issues	Queries related to content curation and copyright issues	content@ndl.gov.in
7	National Digital Library of India Club (NDLI Club)	Queries related to NDLI Club formation, support, user awareness program, seminar/symposium, collaboration, social media, promotion, and outreach	clubsupport@ndl.gov.in
8	Digital Preservation Centre (DPC)	Assistance with digitizing and archiving copyright-free printed books	dpc@ndl.gov.in
9	IDR Setup or Support	Queries related to establishment and support of Institutional Digital Repository (IDR) and IDR workshops	idr@ndl.gov.in

Mechanism of proton-coupled quinone reduction in Photosystem II

Energetics of the exchangeable quinone, Q B , in Photosystem II

Redox potential of the terminal quinone electron acceptor $Q_{B}$ in photosystem II reveals the mechanism of electron transfer regulation

Light-induced quinone reduction in photosystem II☆

Mechanism of tyrosine D oxidation in Photosystem II

Water oxidation mechanism in photosystem II, including oxidations, proton release pathways, O―O bond formation and $O_{2}$ release☆

Inhibition of the Water Oxidizing Complex of Photosystem II and the Reoxidation of the Quinone Acceptor QA − by Pb2+

Changes in [14C]Atrazine Binding Associated with the Oxidation-Reduction State of the Secondary Quinone Acceptor of Photosystem II 1

Cationic screening of charged surface groups (carboxylates) affects electron transfer steps in photosystem-II water oxidation and quinone reduction

Mechanism of proton-coupled quinone reduction in Photosystem II

Similar Documents

Mechanism of proton-coupled quinone reduction in Photosystem II

Energetics of the exchangeable quinone, Q B , in Photosystem II

Redox potential of the terminal quinone electron acceptor $Q_{B}$ in photosystem II reveals the mechanism of electron transfer regulation

Light-induced quinone reduction in photosystem II☆

Mechanism of tyrosine D oxidation in Photosystem II

Water oxidation mechanism in photosystem II, including oxidations, proton release pathways, O―O bond formation and $O_{2}$ release☆

Inhibition of the Water Oxidizing Complex of Photosystem II and the Reoxidation of the Quinone Acceptor QA − by Pb2+

Changes in [14C]Atrazine Binding Associated with the Oxidation-Reduction State of the Secondary Quinone Acceptor of Photosystem II 1

Cationic screening of charged surface groups (carboxylates) affects electron transfer steps in photosystem-II water oxidation and quinone reduction

Mechanism of proton-coupled quinone reduction in Photosystem II