Exploring the Structure of the 100 Amino-Acid Residue Long N-Terminus of the Plant Antenna Protein CP29

摘要: The structure of the unusually long (∼100 amino-acid residues) N-terminal domain light-harvesting protein CP29 plants is not defined in crystal this membrane protein. We studied N-terminus using two electron paramagnetic resonance (EPR) approaches: rotational diffusion spin labels at 55 residues with continuous-wave EPR, and three sets distances a pulsed EPR method. relatively structured. Five regions that differ considerably their dynamics are identified. Two have low diffusion, one which shows α-helical character suggesting contact surface. This immobile part flanked by highly dynamic, unstructured (loops) cover 10–22 82–91. These loops may be important for interaction other proteins. region around residue 4 also has presumably because it attaches noncovalently to section close phosphorylation site (Thr-6) related proteins, such as those encoded Lhcb4.2 gene. Phosphorylation might influence antenna complexes, thereby regulating supramolecular organization thylakoid membrane.