Structural investigation of PsbO from plant and cyanobacterial photosystem II.
The manganese-stabilizing protein PsbO is associated with the luminal side of thylakoids close to the redox-active Mn(4)Ca cluster at the catalytically active site of photosystem II (PSII). PsbO is believed to increase the efficiency of oxygen evolution and to stabilize the Mn(4)Ca cluster against photoinhibition. Using small-angle X-ray scattering, we investigated the low-resolution structure of wild-type spinach PsbO and that of chimeric spinach PsbO fused with maltose-binding protein. Small-angle X-ray scattering data revealed that both proteins are monomeric in solution, and that plant and cyanobacterial PsbO have similar structures. We show a highly efficient expression system that allows recombinant production of the active wild type and the chimeric PsbO from spinach and cyanobacteria, with yields compatible with biophysical and structural studies. The binding of spinach PsbO fused with maltose-binding protein to PSII depleted of extrinsic subunits (PSII-ΔpsbO,P,Q) was confirmed by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. The reconstituted PSII was shown to have similar oxygen evolution rates as obtained with wild-type spinach PsbO.
Max Volmer Laboratory of Biophysical Chemistry, Technische Universität Berlin, Strasse des 17, Juni 135, 10623 Berlin, Germany. dslowik@mrc-lmb.cam.ac.uk
Daria
D
Slowik
Maxim
M
Rossmann
Petr V
PV
Konarev
Klaus-D
KD
Irrgang
Wolfram
W
Saenger
D015153:Blotting, Western; D020134:Catalytic Domain; D002942:Circular Dichroism; D000458:Cyanobacteria / Q000254:growth & development / Q000378:metabolism*; D058619:Maltose-Binding Proteins / Q000378:metabolism*; D008345:Manganese / Q000378:metabolism; D008958:Models, Molecular; D010100:Oxygen / Q000378:metabolism; D045332:Photosystem II Protein Complex / Q000737:chemistry* / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry* / Q000378:metabolism; D011485:Protein Binding; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013056:Spectrophotometry, Ultraviolet; D018724:Spinacia oleracea / Q000254:growth & development / Q000378:metabolism*
D058619:Maltose-Binding Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; C052389:oxygen-evolving enhancer protein 1, plant; D008345:Manganese; D010100:Oxygen