Measurement of the g-tensor of the P700+. signal from deuterated cyanobacterial photosystem I particles.
We report high-field continuous wave EPR spectra of P700+. in preparations obtained from deuterated cyanobacteria (Synechococcus lividus). Measurements were performed with photosystem I (PS-I) preparations, whole cells from cyanobacteria grown in 2H2O, and photosystem II (PS-II) preparations, as well as with protonated PS-I preparations. Because of the significantly improved resolution of our 140-GHz spectrometer (as compared with X- or Q-band EPR) the principal values of the g-tensor of the primary donor P700+. could be resolved and measured with high accuracy as g11 = 2.00304, g22 = 2.00262, and g33 = 2.00232. Other signals arising from Mn2+ and a dark signal from PS-II at g approximately 2.00266 are distinguished from the P700+. g-tensor powder pattern. The measured g values are compared with those of several bacterial reaction center donors.
Prisner
T F
TF
Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139.
McDermott
A E
AE
Un
S
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Norris
J R
JR
Thurnauer
M C
MC
Griffin
R G
RG
D000458:Cyanobacteria / Q000502:physiology*; D003903:Deuterium; D004578:Electron Spin Resonance Spectroscopy; D066298:In Vitro Techniques; D045322:Photosynthetic Reaction Center Complex Proteins / Q000378:metabolism*
D045322:Photosynthetic Reaction Center Complex Proteins; D003903:Deuterium