Light-harvesting proteins harness light energy for photosynthesis. Sequences of the Photosystem II (PS II) light harvesting proteins, Lhcb1-6, have been deduced from many plants. However, limited information is available for spinach Lhcb sequences, although a spinach PS II preparation (BBY) is commonly used as a model for plant photosynthetic oxygen evolution [DA Berthold, GT Babcock and CF Yocum (1981) FEBS Lett 134: 231-234]. In this work, we describe the use of tryptic digestion, liquid chromatography, tandem mass spectrometry, and database searching to identify light-harvesting proteins in the spinach BBY preparation. Using this approach, partial amino acid sequences were assigned to the PS II-associated light-harvesting proteins, Lhcb1-6. The identified stretches of sequence are predicted to contain intra-membranous chlorophyll ligands, extra-membranous loop regions, and lutein-binding sites. In addition, we find that at least two distinct Lhcb4 (CP29) polypeptides and two distinct Lhcb1 polypeptides are present in the BBY preparation. One of these Lhcb4 polypeptides has a subsequence that has not been reported for Lhcb4 in any other organism. This work demonstrates the utility of tandem mass spectrometry in the characterization of photosynthetic membrane proteins.
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http://dx.doi.org/10.1023/A:1016132700844 | DOI Listing |
Anal Chem
January 2025
Department of Electrical Engineering and Electronics, University of Liverpool, Liverpool L69 3BX, U.K.
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GuiZhou Institute of Subtropical Crops, Guizhou Academy of Agricultural Sciences, Guiyang, China.
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Am J Transl Res
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Department of Pharmacy, The Fourth Hospital of Hebei Medical University Shijiazhuang 050000, Hebei, China.
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View Article and Find Full Text PDFAnn Intensive Care
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