Determination of photosystem II subunits by matrix-assisted laser desorption/ionization mass spectrometry.
Photosystem II of higher plants and cyanobacteria is composed of more than 20 polypeptide subunits. The pronounced hydrophobicity of these proteins hinders their purification and subsequent analysis by mass spectrometry. This paper reports the results obtained by application of matrix-assisted laser desorption/ionization mass spectrometry directly to isolated complexes and thylakoid membranes prepared from cyanobacteria and spinach. Changes in protein contents following physiopathological stimuli are also described. Good correlations between expected and measured molecular masses allowed the identification of the main, as well as most of the minor, low molecular weight components of photosystem II. These results open up new perspectives for clarifying the functional role of the various polypeptide components of photosystems and other supramolecular integral membrane complexes.
Department of Biology, University of Padova, Via G. Colombo 3, 35131 Padova, Italy.
I
I
Szabò
R
R
Seraglia
F
F
Rigoni
P
P
Traldi
G M
GM
Giacometti
D002851:Chromatography, High Pressure Liquid; D000458:Cyanobacteria / Q000737:chemistry* / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D009154:Mutation; D010455:Peptides / Q000737:chemistry; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000235:genetics; D045332:Photosystem II Protein Complex; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*; D018724:Spinacia oleracea / Q000737:chemistry*; D020524:Thylakoids / Q000378:metabolism; D014466:Ultraviolet Rays
D010455:Peptides; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex