Abstract
The exact color of light absorbed by chlorophyll (Chl) pigments, the light-harvesters in photosynthesis, is tuned by the protein microenvironment, but without knowledge of the intrinsic color of Chl it remains unclear how large this effect is. Experimental first absorption energies of Chl a and b isolated in vacuo and tagged with quaternary ammonium cations are reported. The energies are largely insensitive to details of the tag structure, a finding supported by first-principles calculations using time-dependent density functional theory. Absorption is significantly blue-shifted compared to that of Chlcontaining proteins (by 30-70 nm). A single red-shifting perturbation, such as axial ligation or the protein medium, is insufficient to account even for the smallest shift; the largest requires pigment-pigment interactions.
Original language | English |
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Pages (from-to) | 2170-2173 |
Number of pages | 4 |
Journal | Angewandte Chemie - International Edition |
Volume | 54 |
Issue number | 7 |
DOIs | |
State | Published - 9 Feb 2015 |
Bibliographical note
Publisher Copyright:© 2015 Wiley-VCH Verlag GmbH & Co. KGaA.
Funding
Funders | Funder number |
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European Commission | FP7 CRONOS 280879-2 |
European Commission | ERC-2010-AdG-267374, FIS2013-46159-C3-1-P |
Seventh Framework Programme | 267374, 280879 |
Keywords
- Action spectroscopy
- Chlorophyll
- Color tuning
- Photosynthesis
- Time-dependent density functional theory