The S(1) split signal of photosystem II; a tyrosine-manganese coupled interaction.
Detailed optical and EPR analyses of states induced in dark-adapted PS II membranes by cryogenic illumination permit characterization and quantification of all pigment derived donors and acceptors, as well as optically silent (in the visible, near infrared) species which are EPR active. Near complete turnover formation of Q(A)((-)) is seen in all centers, but with variable efficiency, depending on the donor species. In minimally detergent-exposed PS II membranes, negligible (<5%) oxidation of chlorophyll or carotenoid centers occurs for illumination temperatures 5-20 K. An optically silent electron donor to P680(+) is observed with the same decay kinetics as the S(1) split signal. Cryogenic donors to P680(+) seen are: (i) transient (t(1/2) approximately 150 s) tyrosine related species, including 'split signals' ( approximately 15% total centers), (ii) reduced cytochrome b(559) ( approximately 30-50% centers), and (iii) an organic donor, possibly an amino acid side chain, ( approximately 30% centers).
Cox
Nicholas
N
Department of Chemistry, College of Science, Australian National University, Canberra, ACT 0200, Australia.
Ho
Felix M
FM
Pewnim
Naray
N
Steffen
Ronald
R
Smith
Paul J
PJ
Havelius
Kajsa G V
KG
Hughes
Joseph L
JL
Debono
Lesley
L
Styring
Stenbjörn
S
Krausz
Elmars
E
Pace
Ron J
RJ
D002338:Carotenoids / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism; D045303:Cytochromes b / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy; D007700:Kinetics; D008027:Light; D008345:Manganese / Q000378:metabolism*; D010084:Oxidation-Reduction; D010777:Photochemistry; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D015398:Signal Transduction; D013055:Spectrophotometry, Infrared; D013696:Temperature; D014443:Tyrosine / Q000378:metabolism*
D045332:Photosystem II Protein Complex; D002734:Chlorophyll; D002338:Carotenoids; D014443:Tyrosine; D008345:Manganese; D045303:Cytochromes b