The functional sites of chlorophylls in D1 and D2 subunits of Photosystem II identified by pulsed EPR |
| |
| Authors: | A Kawamori T-A Ono A Ishii S Nakazawa H Hara T Tomo J Minagawa R Bittl SA Dzuba |
| |
| Institution: | (1) School of Science and Technology, Kwansei Gakuin University, Sanda, Japan;(2) The Institute of Physical and Chemical Research (RIKEN), Photodynamics Research Center, Sendai, Japan;(3) Division of EPR Application, Bruker Biospin, KK., Tsukuba, Japan;(4) Department of Physics, College of Humanities and Sciences, Nihon University, Tokyo, Japan;(5) Low Temperature Research Institute, Hokkaido University, Sapporo, Japan;(6) Institute of Experimental Physics, Free University of Berlin, Berlin, Germany;(7) Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk, Russia |
| |
| Abstract: | The functional site of ChlZ, an auxiliary electron donor to P680+, was determined by pulsed ELDOR applied to a radical pair of YD• and Chlz+ in oriented PS II membranes from spinach. The radical-radical distance was determined to be 29.5 Å and its direction was 50° from the membrane normal, indicating that a chlorophyll on the D2 protein is responsible for the EPR Chlz+ signal. Spin polarized ESEEM (Electronin Spin Echo Envelop Modulation) of a 3Chl and QA− radical pair induced by a laser flash was observed in reaction center D1D2Cytb559 complex, in which QA was functionally reconstituted with DBMIB and reduced chemically. QA−ESEEM showed a characteristic oscillating time profile due to dipolar coupling with 3Chl. By fitting with the dipolar interaction parameters, the distance between 3Chl and QA− was determined to be 25.9 Å, indicating that the accessory chlorophyll on the D1 protein is responsible for the 3Chl signal. |
| |
| Keywords: | Chlamydomonas chlorophyll Z PS II pulsed EPR triplet chlorophyll YD-less mutant |
| 本文献已被 PubMed SpringerLink 等数据库收录！ |
|
