title: Light-induced FTIR difference spectroscopy of the S(2)-to-S(3) state transition of the oxygen-evolving complex in Photosystem II.
abstract: We have applied flash-induced FTIR spectroscopy to study structural changes upon the S(2)-to-S(3) state transition of the oxygen-evolving complex (OEC) in Photosystem II (PSII). We found that several modes in the difference IR spectrum are associated with bond rearrangements induced by the second laser flash. Most of these IR modes are absent in spectra of S(2)/S(1), of the acceptor-side non-heme ion, of Yradical(D)/Y(D) and of S(3)'/S(2)' from Ca-depleted PSII preparations. Our results suggest that these IR modes most likely originate from structural changes in the oxygen-evolving complex itself upon the S(2)-to-S(3) state transition in PSII.
authors.affiliation: Department of Chemistry, Michigan State University, East Lansing 48824, USA.
authors.forename: H A
authors.initials: HA
authors.lastname: Chu
authors.forename: W
authors.initials: W
authors.lastname: Hillier
authors.forename: N A
authors.initials: NA
authors.lastname: Law
authors.forename: H
authors.initials: H
authors.lastname: Sackett
authors.forename: S
authors.initials: S
authors.lastname: Haymond
authors.forename: G T
authors.initials: GT
authors.lastname: Babcock
mesh_terms: D007834:Lasers; D008027:Light; D010100:Oxygen / Q000032:analysis / Q000737:chemistry*; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D045332:Photosystem II Protein Complex; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010100:Oxygen