A systematic survey of conserved histidines in the core subunits of Photosystem I by site-directed mutagenesis reveals the likely axial ligands of P700

Redding, K., MacMillan, F., Leibl, W., Brettel, K., Hanley, J., Rutherford, A.W., Breton, J. and Rochaix, J.-D. (1998) A systematic survey of conserved histidines in the core subunits of Photosystem I by site-directed mutagenesis reveals the likely axial ligands of P700. The EMBO Journal, 17 (1). pp. 50-60. ISSN 0261-4189

Full text not available from this repository. (Request a copy)

Abstract

The Photosystem I complex catalyses the transfer of an electron from lumenal plastocyanin to stromal ferredoxin, using the energy of an absorbed photon. The initial photochemical event is the transfer of an electron from the excited state of P, a pair of chlorophylls, to a monomer chlorophyll serving as the primary electron acceptor. We have performed a systematic survey of conserved histidines in the last six transmembrane segments of the related polytopic membrane proteins PsaA and PsaB in the green alga Chlamydomonas reinhardtii. These histidines, which are present in analogous positions in both proteins, were changed to glutamine or leucine by site-directed mutagenesis. Double mutants in which both histidines had been changed to glutamine were screened for changes in the characteristics of P using electron paramagnetic resonance, Fourier transform infrared and visible spectroscopy. Only mutations in the histidines of helix 10 (PsaA-His676 and PsaB-His656) resulted in changes in spectroscopic properties of P, leading us to conclude that these histidines are most likely the axial ligands to the P chlorophylls.

Item Type: Article
Faculty \ School: Faculty of Science > School of Chemistry
University of East Anglia > Faculty of Science > Research Groups > Biophysical Chemistry
Related URLs:
Depositing User: Pure Connector
Date Deposited: 21 Jan 2015 11:48
Last Modified: 25 Jul 2018 10:24
URI: https://ueaeprints.uea.ac.uk/id/eprint/51854
DOI: 10.1093/emboj/17.1.50

Actions (login required)

View Item