HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Schroder, W. P. Articles by Renger, G. Search for Related Content PubMed PubMed Citation Articles by Schroder, W. P. Articles by Renger, G. Social Bookmarking                      What's this?

J. Biol. Chem., Vol. 269, Issue 52, 32865-32870, 12, 1994

Flash-induced absorption spectroscopy studies of copper interaction with photosystem II in higher plants

WP Schroder, JB Arellano, T Bittner, M Baron, HJ Eckert and G Renger
Department of Biochemistry, Arrhenius Laboratories for Natural Sciences, Stockholm University, Sweden.

Measurements of flash-induced absorption changes at 325, 436, and 830 nm and of oxygen evolution were performed in order to analyze in detail the inhibition of photosystem II (PS II) by Cu(II) in PS II membrane fragments from spinach. (a) The kinetics of P680+ reduction become markedly slower in the presence of 100 microM CuSO4. (b) The CuSO4- induced kinetics of P680+ reduction are dominated by a 140-160- microsecond decay. (c) The extent of these 140-160-microsecond kinetics, normalized to the overall decay, remains virtually unaffected by addition of the exogenous PS II donor, NH2OH. (d) In thoroughly dark- adapted samples the CuSO4-induced 140-160-microsecond kinetics are already observed after the first flash and remain unchanged by a train of excitation flashes. (e) The extent of P680+ and QA- formation under repetitive flash excitation is not diminished by addition of 100 microM CuSO4. (f) The induction of microsecond kinetics of P680+ reduction at the expense of ns kinetics and the inhibition of the saturation rate of oxygen evolution exhibit the same dependence on CuSO4 concentration. (g) CuSO4 also transforms the 10-20-microsecond reduction of P680+ by TyrZ in Tris-washed PS II membrane fragments into 140-160-microsecond kinetics without any effect on the extent of flash-induced P680+ formation. These results unambiguously show that Cu(II) does not affect the charge separation (P680+QA-), but instead specifically modifies TyrZ and/or its micro environment so that the electron transfer to P680+ becomes blocked.
CiteULike    Complore    Connotea    Del.icio.us    Digg    Reddit    Technorati    What's this?

This article has been cited by other articles:

				I. Yruela, J. J. Pueyo, P. J. Alonso, and R. Picorel Photoinhibition of Photosystem II from Higher Plants. EFFECT OF COPPER INHIBITION J. Biol. Chem., November 1, 1996; 271(44): 27408 - 27415. [Abstract] [Full Text] [PDF]