Papers

Peer-reviewed
Aug, 2012

Determination of the Miss Probabilities of Individual S-State Transitions during Photosynthetic Water Oxidation by Monitoring Electron Flow in Photosystem II Using FTIR Spectroscopy

BIOCHEMISTRY
  • Hiroyuki Suzuki
  • ,
  • Miwa Sugiura
  • ,
  • Takumi Noguchi

Volume
51
Number
34
First page
6776
Last page
6785
Language
English
Publishing type
Research paper (scientific journal)
DOI
10.1021/bi300708a
Publisher
AMER CHEMICAL SOC

Water oxidation by plants and cyanobacteria is performed via a light-driven cycle of five intermediates called S states (S-0-S-4) at the water oxidizing center (WOC) in photosystem II (PSII). The information about misses, i.e., the probabilities that the S-state transitions failed to advance, is crucial for detailed analysis of various spectroscopic data in investigations of the water oxidation mechanism. In this study, we have determined the miss probabilities of the individual S-state transitions using light induced Fourier transform infrared (FTIR) difference spectroscopy. The extent of S-state transitions in the WOC upon each saturating flash was monitored by detecting the flow of electrons from the WOC to ferricyanide, an exogenous electron acceptor, using the CN stretching bands of ferricyanide and ferrocyanide. Simulation of the oscillation pattern of the flash-number dependence of the signal amplitude provided the miss probabilities for the S-0 -> S-1, S-1 -> S-2, S-2 -> S-3, and S-3 -> S-0 transitions (alpha(0)-alpha(3), respectively) without any assumption about fitting parameters. The results for PSII preparations from Thermosynechococcus elongatus and spinach showed a general tendency of misses in the order, alpha(0) <= alpha(1) < alpha(2) < alpha(3), indicating that a more oxidized WOC has a higher miss probability. A very similar result observed for the Y-D-less mutant (D2-Y160F) of T. elongatus confirmed that Y-D does not affect the estimated misses. It was further shown that NO3- treatment specifically increased alpha(3), consistent with inactivation of the S-3 state reported previously. These results demonstrate the usefulness of this FTIR method for estimating individual miss probabilities in the S-state cycle in elucidation of the molecular mechanism of photosynthetic water oxidation.

Link information
DOI
https://doi.org/10.1021/bi300708a
PubMed
https://www.ncbi.nlm.nih.gov/pubmed/22880689
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000307988600008&DestApp=WOS_CPL
ID information
  • DOI : 10.1021/bi300708a
  • ISSN : 0006-2960
  • Pubmed ID : 22880689
  • Web of Science ID : WOS:000307988600008

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