Light-harvesting complex II in monocomponent and mixed lipid-protein monolayers.
Monomolecular layers at the air-water interface were formed directly with isolated largest light-harvesting pigment-protein complex of Photosystem II (LHC II) or out of egg yolk lecithin (EYL) liposomes containing incorporated LHC II. Pure protein monolayers showed a mean area of 1400 A2 per molecule at the air-water interface. Monolayers were deposited onto glass slides by means of Langmuir-Blodgett (LB) technique. Chlorophyll fluorescence of LHC II-LB and EYL-LHC II-LB films proved energetic coupling of chlorophyll a and b, thus indicating native conformation of LHC II within the monolayers. Scanning force microscopy (SFM) revealed ring-like structures formed in monocomponent protein layers as well as in mixed protein-lipid films. These results suggest that a structural arrangement of LHC II is favoured in a lipid environment but that the protein has itself a strong tendency for structural complex rearrangement in our system.
Kernen
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EMPA, Swiss Federal Laboratories for Materials Testing and Research, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland.
Gruszecki
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WI
Matuta
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M
Wagner
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Ziegler
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U
Krupa
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D002734:Chlorophyll / Q000737:chemistry; D045342:Light-Harvesting Protein Complexes; D050356:Lipid Metabolism; D008081:Liposomes / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry; D018625:Microscopy, Atomic Force; D010713:Phosphatidylcholines / Q000378:metabolism; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry*; D045332:Photosystem II Protein Complex; D018515:Plant Leaves / Q000737:chemistry; D010940:Plant Proteins / Q000737:chemistry; D011312:Pressure; D011487:Protein Conformation; D012434:Secale / Q000737:chemistry*; D013050:Spectrometry, Fluorescence; D013053:Spectrophotometry; D013499:Surface Properties
D045342:Light-Harvesting Protein Complexes; D008081:Liposomes; D008565:Membrane Proteins; D010713:Phosphatidylcholines; D045322:Photosynthetic Reaction Center Complex Proteins; D045332:Photosystem II Protein Complex; D010940:Plant Proteins; D002734:Chlorophyll