Functional organization of photosystem II antenna complexes: CP29 under the spotlight

Pengqi Xu, Laura M. Roy, Roberta Croce*

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


In the first step of the photosynthetic process, light is absorbed by the pigments associated with the antenna proteins, known as light-harvesting complexes (Lhcs), which in vivo are functionally organized as hetero-oligomers. The architecture of the pigments, chlorophylls, and carotenoids bound to each LHC is responsible for the efficient excitation energy transfer resulting in photochemistry. So far, the only LHC studied in depth was LHCII, the most abundant membrane protein of plants, while less information was available for the other antennae. In particular, despite the availability of the structure of CP29 obtained at near atomic resolution in 2011 (Pan et al., 2011), the mismatch in pigment content and spectroscopic properties between CP29 in solution and in the crystal has hampered the possibility to use the structure to interpret the experimental data. In this work, we purified CP29 and its larger assembly (CP29-LHCII-CP24) from the membrane in very mild conditions using a His-tag, and we have studied their pigment binding and spectroscopic properties. In addition, we have performed mutation analysis in vivo to obtain mutants of CP29 lacking individual chlorophylls. The peculiar properties of this antenna support its role in directing the energy flow from the external antennae to the reaction center.

Original languageEnglish
Pages (from-to)815-822
Number of pages8
JournalBiochimica et Biophysica Acta - Bioenergetics
Issue number10
Publication statusPublished - 1 Oct 2017


  • CP29
  • In vivo mutation analysis
  • Light-harvesting complexes
  • Photosystem II
  • PSII supercomplexes


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