Phosphorylation controls the three-dimensional structure of plant light harvesting complex II.
The most abundant chlorophyll-binding complex in plants is the intrinsic membrane protein light-harvesting complex II (LHC II). LHC II acts as a light-harvesting antenna and has an important role in the distribution of absorbed energy between the two photosystems of photosynthesis. We used spectroscopic techniques to study a synthetic peptide with identical sequence to the LHC IIb N terminus found in pea, with and without the phosphorylated Thr at the 5th amino acid residue, and to study both forms of the native full-length protein. Our results show that the N terminus of LHC II changes structure upon phosphorylation and that the structural change resembles that of rabbit glycogen phosphorylase, one of the few phosphoproteins where both phosphorylated and non-phosphorylated structures have been solved. Our results indicate that phosphorylation of membrane proteins may regulate their function through structural protein-protein interactions in surface-exposed domains.
Nilsson
A
A
Plant Cell Biology, Box 7007, Lund University, S-220 07 Lund, Sweden.
Stys
D
D
Drakenberg
T
T
Spangfort
M D
MD
Forsén
S
S
Allen
J F
JF
D000595:Amino Acid Sequence; D000818:Animals; D002942:Circular Dichroism; D006863:Hydrogen-Ion Concentration; D045342:Light-Harvesting Protein Complexes; D008961:Models, Structural; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000737:chemistry; D010750:Phosphoproteins / Q000737:chemistry* / Q000378:metabolism; D006005:Phosphorylases / Q000737:chemistry; D010766:Phosphorylation; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry* / Q000378:metabolism; D017433:Protein Structure, Secondary; D011817:Rabbits; D013053:Spectrophotometry; D017550:Spectroscopy, Fourier Transform Infrared
D045342:Light-Harvesting Protein Complexes; D010446:Peptide Fragments; D010750:Phosphoproteins; D045322:Photosynthetic Reaction Center Complex Proteins; D006005:Phosphorylases