Measurement of the g-tensor of the P700(+.) signal from deuterated cyanobacterial photosystem I particles

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 90; no. 20; pp. 9485 - 9488
• Main Authors: Prisner, Thomas F., McDermott, Ann E., Un, Sun, Norris, James R., Thurnauer, Marion C., Griffin, Robert G.
• Format: Journal Article
• Language: English
• Published: Washington, DC National Academy of Sciences of the United States of America 15-10-1993; National Acad Sciences; National Academy of Sciences
• Subjects: 400201 - Chemical & Physicochemical Properties; Anisotropy; Bacteria; Biochemistry; biochimie; Biological and medical sciences; Biology; bioquimica; Crystal structure; Cyanobacteria; Cyanobacteria - physiology; cyanophyta; Deuterium; Electric fields; ELECTRON SPIN RESONANCE; Electron Spin Resonance Spectroscopy; Electrons; Enzymes; fotosistemas; Fundamental and applied biological sciences. Psychology; In Vitro Techniques; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; Magnetic fields; MAGNETIC RESONANCE; Molecular biophysics; MOLECULAR STRUCTURE; Photosynthetic Reaction Center Complex Proteins - metabolism; PHOTOSYNTHETIC REACTION CENTERS; Photosystem I; photosysteme; photosystems; Physics; PIGMENTS; RADICALS; RESONANCE; Spectroscopy : techniques and spectras; STRUCTURAL CHEMICAL ANALYSIS; Superhigh frequencies; Photosystem 1; Photosynthetic particle; Cyanobacteria; EPR spectrometry; Synechococcus; P700 pigment; Bacteria; Cations; g factor; Deuteriation; Free radical
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.90.20.9485

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 web 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.