title: Tetranitromethane modification of photosystem 2.
abstract: Inhibition of photosystem 2 by the peptide-modification reagent, tetranitromethane, has been investigated with spinach digitonin particles. In the presence of tetranitromethane, (1) the initial fluoresence yield is suppressed with a concomitant elimination of the variable component of fluorescence; (2) the optical absorption transient at 820 nm, attributed to P680(+), is greatly attenuated; (3) diphenylcarbazide-supported photoreduction of dichlorophenol indophenol is abolished; and (4) electron spin resonance Signal 2f and Signal 2s are eliminated. These results are consistent with multiple sites of modification in photosystem 2 by tetranitromethane, and suggest further that this reagent can inhibit charge stabilization in the reaction center.
authors.affiliation: Department of Chemistry, Rensselaer Polytechnic Institute, 12180-3590, Troy, NY, USA.
authors.forename: C
authors.initials: C
authors.lastname: Walczak
authors.forename: S
authors.initials: S
authors.lastname: Kumar
authors.forename: J T
authors.initials: JT
authors.lastname: Warden