Chelator-induced disappearance of carboxylate stretching vibrational modes in S2/S1 FTIR spectrum in oxygen-evolving complex of photosystem II

被引:38
作者
Kimura, Y [1 ]
Ono, TA [1 ]
机构
[1] Inst Phys & Chem Res, RIKEN, Photodynam Res Ctr, Lab Photobiol 1,Aoba Ku, Sendai, Miyagi 9800845, Japan
关键词
D O I
10.1021/bi011216w
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
Fourier transform infrared (FTIR) spectroscopy has been applied toward studies of photosynthetic oxygen evolution, especially on the effects of Call depletion and chelating agents using S-2/S-1 FTIR difference spectrum in the mid-IR region. Ca2+ depletion showed little influences on the symmetric (1365/1404 cm(-1)) and the asymmetric (1587/1562 cm-1) stretching bands of a carboxylate, which are typical of the S-2/S-1 vibrational features induced by the oxidation of the Mn-cluster; however, minor changes were observed in the amide regions. Addition of a chelating agent (EDTA or EGTA) to the Ca2+-depleted membranes resulted in the disappearance of the carboxylate bands concurrent with large modifications of the amide bands with an apparent K-d value of approximately 0.49 MM (for EDTA). The carboxylate bands and the greater part of the amide bands were restored by the replenishment of CaCl2, and the chelators did not affect the spectrum in the nondepleted control membranes, indicating that the effects of the chelator are reversible and manifest only in the cases in which the Ca2+ site is unoccupied by Ca2+. Ca2+-depleted membranes showed the normal S(2)Q(A)(-) thermoluminescence band, and further addition of EDTA did not show any effects on the peak temperature and peak intensity. Moreover, the Ca2+-depleted membranes in the presence of EDTA exhibited the S-2 multiline EPR signal with nearly the normal hyperfine splittings. These results demonstrated that the Mn-cluster is oxidized to the S-2 state with normal redox and magnetic properties in the presence of the chelator despite the loss of the carboxylate bands in the FTIR spectra. The results are interpreted as indicating that the chelator interacts with the Mn-cluster as a replacement of the native carboxylate ligand. This prevents the structural changes of the Mn-cluster and protein backbone which are induced upon the oxidation of the Mn-cluster up to the S-2 state, but preserve the redox and magnetic properties of the S-2 state Mn-cluster. The roles of Ca2+ in the photosynthetic oxygen evolution are also discussed.
引用
收藏
页码:14061 / 14068
页数:8
相关论文
共 41 条
[1]   A HIGHLY RESOLVED, OXYGEN-EVOLVING PHOTOSYSTEM-II PREPARATION FROM SPINACH THYLAKOID MEMBRANES - ELECTRON-PARAMAGNETIC-RES AND ELECTRON-TRANSPORT PROPERTIES [J].
BERTHOLD, DA ;
BABCOCK, GT ;
YOCUM, CF .
FEBS LETTERS, 1981, 134 (02) :231-234
[2]   CHARACTERIZATION BY FTIR SPECTROSCOPY OF THE PHOTOREDUCTION OF THE PRIMARY QUINONE ACCEPTOR QA IN PHOTOSYSTEM-II [J].
BERTHOMIEU, C ;
NABEDRYK, E ;
MANTELE, W ;
BRETON, J .
FEBS LETTERS, 1990, 269 (02) :363-367
[3]   Location of the calcium binding site in Photosystem II: A Mn2+ substitution study [J].
Booth, PJ ;
Rutherford, AW ;
Boussac, A .
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 1996, 1277 (1-2) :127-134
[4]   FACTORS INFLUENCING THE FORMATION OF MODIFIED S2 EPR SIGNAL AND THE S3 EPR SIGNAL IN CA-2+-DEPLETED PHOTOSYSTEM-II [J].
BOUSSAC, A ;
ZIMMERMANN, JL ;
RUTHERFORD, AW .
FEBS LETTERS, 1990, 277 (1-2) :69-74
[5]   EPR SIGNALS FROM MODIFIED CHARGE ACCUMULATION STATES OF THE OXYGEN EVOLVING ENZYME IN CA-2+-DEFICIENT PHOTOSYSTEM-II [J].
BOUSSAC, A ;
ZIMMERMANN, JL ;
RUTHERFORD, AW .
BIOCHEMISTRY, 1989, 28 (23) :8984-8989
[6]   NATURE OF THE INHIBITION OF THE OXYGEN-EVOLVING ENZYME OF PHOTOSYSTEM-II INDUCED BY NACL WASHING AND REVERSED BY THE ADDITION OF CA-2+ OR SR-2+ [J].
BOUSSAC, A ;
RUTHERFORD, AW .
BIOCHEMISTRY, 1988, 27 (09) :3476-3483
[7]   Identification of a Mn-O-Mn cluster vibrational mode of the oxygen-evolving complex in photosystem II by low-frequency FTIR spectroscopy [J].
Chu, HA ;
Sackett, H ;
Babcock, GT .
BIOCHEMISTRY, 2000, 39 (47) :14371-14376
[8]   D1-Asp170 is structurally coupled to the oxygen evolving complex in photosystem II as revealed by light-induced Fourier transform infrared difference spectroscopy [J].
Chu, HA ;
Debus, RJ ;
Babcock, GT .
BIOCHEMISTRY, 2001, 40 (07) :2312-2316
[9]   Vibrational spectroscopy of the oxygen-evolving complex and of manganese model compounds [J].
Chu, HA ;
Hillier, W ;
Law, NA ;
Babcock, GT .
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 2001, 1503 (1-2) :69-82
[10]   Light-induced FTIR difference spectroscopy of the S2-to-S3 state transition of the oxygen-evolving complex in Photosystem II [J].
Chu, HA ;
Hillier, W ;
Law, NA ;
Sackett, H ;
Haymond, S ;
Babcock, GT .
BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS, 2000, 1459 (2-3) :528-532