2C9E

Peridinin-chlorophyll a protein, high-salt form

Summary for 2C9E

• Entry DOI: 10.2210/pdb2c9e/pdb
• Descriptor: PERIDININ-CHLOROPHYLL A PROTEIN, CHLOROPHYLL A, PERIDININ, ... (6 entities in total)
• Functional Keywords: photosynthesis, carotenoids, chloroplast, light harvesting protein, light-harvesting polypeptide, multigene family, transit peptide
• Biological source: AMPHIDINIUM CARTERAE (DINOFLAGELLATE)
• Total number of polymer chains: 1
• Total formula weight: 42182.18

Authors

Schulte, T.,Sharples, F.P.,Hiller, R.G.,Hofmann, E. (deposition date: 2005-12-09, release date: 2007-02-20, Last modification date: 2023-12-13)

Primary citation

Schulte, T.,Sharples, F.P.,Hiller, R.G.,Hofmann, E.
X-Ray Structure of the High-Salt Form of the Peridinin-Chlorophyll A-Protein from the Dinoflagellate Amphidinium Carterae: Modulation of the Spectral Properties of Pigments by the Protein Environment.
Biochemistry, 48:4466-, 2009

PubMed Abstract: Light-harvesting complexes have evolved into very different structures but fulfill the same function, efficient harvesting of solar energy. In these complexes, pigments are fine-tuned and properly arranged to gather incoming photons. In the photosynthetic dinoflagellate Amphidinium carterae, two variants of the soluble light-harvesting complex PCP have been found [main form PCP (MFPCP) and high-salt PCP (HSPCP)], which show small variations in their pigment arrangement and tuning mechanisms. This feature makes them ideal models for studying pigment-protein interactions. Here we present the X-ray structure of the monomeric HSPCP determined at 2.1 A resolution and compare it to the structure of trimeric MFPCP. Despite the high degree of structural similarity (rmsd C(alpha)-C(alpha) of 1.89 A), the sequence variations lead to a changed overall pigment composition which includes the loss of two carotenoid molecules and a dramatic rearrangement of the chlorophyll phytol chains and of internal lipid molecules. On the basis of a detailed structural comparison, we favor a macrocycle geometry distortion of the chlorophylls rather than an electrostatic effect to explain energetic splitting of the chlorophyll a Q(y) bands [Ilagan, R. P. (2006) Biochemistry 45, 14052-14063]. Our analysis supports their assignment of peridinin 611* as the single blue-shifted peridinin in HSPCP but also highlights another electrostatic feature due to glutamate 202 which could add to the observed binding site asymmetry of the 611*/621* peridinin pair.

PubMed: 19371099
DOI: 10.1021/BI802320Q

Experimental method

X-RAY DIFFRACTION (2.1 Å)