Abstract
Transient absorption spectroscopy has been applied to investigate the energy dissipation mechanisms in the nonameric fucoxanthin-chlorophyll-a,c-binding protein FCPb of the centric diatom Cyclotella meneghiniana. FCPb complexes in their unquenched state were compared with those in two types of quenching environments, namely aggregation-induced quenching by detergent removal, and clustering via incorporation into liposomes. Applying global and target analysis, in combination with a fluorescence lifetime study and annihilation calculations, we were able to resolve two quenching channels in FCPb that involve chlorophyll-a pigments for FCPb exposed to both quenching environments. The fast quenching channel operates on a timescale of tens of picoseconds and exhibits similar spectral signatures as the unquenched state. The slower quenching channel operates on a timescale of tens to hundreds of picoseconds, depending on the degree of quenching, and is characterized by enhanced population of low-energy states between 680 and 710 nm. The results indicate that FCPb is, in principle, able to function as a dissipater of excess energy and can do this in vitro even more efficiently than the homologous FCPa complex, the sole complex involved in fast photoprotection in these organisms. This indicates that when a complex displays photoprotection-related spectral signatures in vitro it does not imply that the complex participates in photoprotection in vivo. We suggest that FCPa is favored over FCPb as the sole energy-regulating complex in diatoms because its composition can more easily establish the balance between light-harvesting and quenching required for efficient photoprotection.
| Original language | English |
|---|---|
| Pages (from-to) | 1151-1160 |
| Number of pages | 10 |
| Journal | Biochimica et Biophysica Acta - Bioenergetics |
| Volume | 1859 |
| Issue number | 10 |
| Early online date | 27 Jul 2018 |
| DOIs | |
| Publication status | Published - Oct 2018 |
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Keywords
- Diatom
- Fucoxanthin-chlorophyll protein
- Light harvesting antenna
- Nonphotochemical quenching
- Proteoliposome
- Transient absorption spectroscopy
Cite this
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Energy dissipation mechanisms in the FCPb light-harvesting complex of the diatom Cyclotella meneghiniana. / Elnour, Huzifa M.A.M.; Dietzel, Lars; Ramanan, Charusheela; Büchel, Claudia; van Grondelle, Rienk; Krüger, Tjaart P.J.
In: Biochimica et Biophysica Acta - Bioenergetics, Vol. 1859, No. 10, 10.2018, p. 1151-1160.Research output: Contribution to Journal › Article › Academic › peer-review
TY - JOUR
T1 - Energy dissipation mechanisms in the FCPb light-harvesting complex of the diatom Cyclotella meneghiniana
AU - Elnour, Huzifa M.A.M.
AU - Dietzel, Lars
AU - Ramanan, Charusheela
AU - Büchel, Claudia
AU - van Grondelle, Rienk
AU - Krüger, Tjaart P.J.
PY - 2018/10
Y1 - 2018/10
N2 - Transient absorption spectroscopy has been applied to investigate the energy dissipation mechanisms in the nonameric fucoxanthin-chlorophyll-a,c-binding protein FCPb of the centric diatom Cyclotella meneghiniana. FCPb complexes in their unquenched state were compared with those in two types of quenching environments, namely aggregation-induced quenching by detergent removal, and clustering via incorporation into liposomes. Applying global and target analysis, in combination with a fluorescence lifetime study and annihilation calculations, we were able to resolve two quenching channels in FCPb that involve chlorophyll-a pigments for FCPb exposed to both quenching environments. The fast quenching channel operates on a timescale of tens of picoseconds and exhibits similar spectral signatures as the unquenched state. The slower quenching channel operates on a timescale of tens to hundreds of picoseconds, depending on the degree of quenching, and is characterized by enhanced population of low-energy states between 680 and 710 nm. The results indicate that FCPb is, in principle, able to function as a dissipater of excess energy and can do this in vitro even more efficiently than the homologous FCPa complex, the sole complex involved in fast photoprotection in these organisms. This indicates that when a complex displays photoprotection-related spectral signatures in vitro it does not imply that the complex participates in photoprotection in vivo. We suggest that FCPa is favored over FCPb as the sole energy-regulating complex in diatoms because its composition can more easily establish the balance between light-harvesting and quenching required for efficient photoprotection.
AB - Transient absorption spectroscopy has been applied to investigate the energy dissipation mechanisms in the nonameric fucoxanthin-chlorophyll-a,c-binding protein FCPb of the centric diatom Cyclotella meneghiniana. FCPb complexes in their unquenched state were compared with those in two types of quenching environments, namely aggregation-induced quenching by detergent removal, and clustering via incorporation into liposomes. Applying global and target analysis, in combination with a fluorescence lifetime study and annihilation calculations, we were able to resolve two quenching channels in FCPb that involve chlorophyll-a pigments for FCPb exposed to both quenching environments. The fast quenching channel operates on a timescale of tens of picoseconds and exhibits similar spectral signatures as the unquenched state. The slower quenching channel operates on a timescale of tens to hundreds of picoseconds, depending on the degree of quenching, and is characterized by enhanced population of low-energy states between 680 and 710 nm. The results indicate that FCPb is, in principle, able to function as a dissipater of excess energy and can do this in vitro even more efficiently than the homologous FCPa complex, the sole complex involved in fast photoprotection in these organisms. This indicates that when a complex displays photoprotection-related spectral signatures in vitro it does not imply that the complex participates in photoprotection in vivo. We suggest that FCPa is favored over FCPb as the sole energy-regulating complex in diatoms because its composition can more easily establish the balance between light-harvesting and quenching required for efficient photoprotection.
KW - Diatom
KW - Fucoxanthin-chlorophyll protein
KW - Light harvesting antenna
KW - Nonphotochemical quenching
KW - Proteoliposome
KW - Transient absorption spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85051079190&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85051079190&partnerID=8YFLogxK
U2 - 10.1016/j.bbabio.2018.07.009
DO - 10.1016/j.bbabio.2018.07.009
M3 - Article
VL - 1859
SP - 1151
EP - 1160
JO - Biochimica et Biophysica Acta (BBA) - Bioenergetics
JF - Biochimica et Biophysica Acta (BBA) - Bioenergetics
SN - 0005-2728
IS - 10
ER -