Tuning antenna function through hydrogen bonds to chlorophyll a

Manuel J. Llansola-Portoles, Fei Li, Pengqi Xu, Simona Streckaite, Cristian Ilioaia, Chunhong Yang, Andrew Gall, Andrew A. Pascal*, Roberta Croce, Bruno Robert

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review


We describe a molecular mechanism tuning the functional properties of chlorophyll a (Chl-a) molecules in photosynthetic antenna proteins. Light-harvesting complexes from photosystem II in higher plants – specifically LHCII purified with α- or β-dodecyl-maltoside, along with CP29 – were probed by low-temperature absorption and resonance Raman spectroscopies. We show that hydrogen bonding to the conjugated keto carbonyl group of protein-bound Chl-a tunes the energy of its Soret and Qy absorption transitions, inducing red-shifts that are proportional to the strength of the hydrogen bond involved. Chls-a with non-H-bonded keto C131 groups exhibit the blue-most absorption bands, while both transitions are progressively red-shifted with increasing hydrogen-bonding strength – by up 382 & 605 cm−1 in the Qy and Soret band, respectively. These hydrogen bonds thus tune the site energy of Chl-a in light-harvesting proteins, determining (at least in part) the cascade of energy transfer events in these complexes.

Original languageEnglish
Article number148078
Pages (from-to)1-6
Number of pages6
JournalBiochimica et Biophysica Acta - Bioenergetics
Issue number4
Early online date30 Aug 2019
Publication statusPublished - 1 Apr 2020


  • Chl-a
  • Energy regulation
  • Hydrogen bonds
  • Light-harvesting
  • Oxygenic photosynthesis


Dive into the research topics of 'Tuning antenna function through hydrogen bonds to chlorophyll a'. Together they form a unique fingerprint.

Cite this