TY - JOUR
T1 - Microsecond and millisecond dynamics in the photosynthetic protein LHCSR1 observed by single-molecule correlation spectroscopy
AU - Kondo, Toru
AU - Gordon, Jesse B.
AU - Pinnola, Alberta
AU - Dall’Osto, Luca
AU - Bassi, Roberto
AU - Schlau-Cohen, Gabriela S.
N1 - Funding Information:
ACKNOWLEDGMENTS. We thank Dr. Justin Caram for helpful comments. The work was supported by NIH Grant NIH9P41EB015871 for 2D-FLC development and Center for Quantum Molecular Design Phase I Center for Chemical Innovation Grant CHE-1740645 from the NSF for application to LHCs. Work was also supported by the Marie Curie Actions Initial Training Networks Solar Energy to Biomass (SE2B) (Grant 675006-SE2B to R.B and A.P.) and by the Research Projects of National Relevance (PRIN) “HARVEST” (Grant 201795SBA3-004 to L.D.).
Funding Information:
We thank Dr. Justin Caram for helpful comments. The work was supported by NIH Grant NIH9P41EB015871 for 2D-FLC development and Center for Quantum Molecular Design Phase I Center for Chemical Innovation Grant CHE-1740645 from the NSF for application to LHCs. Work was also supported by the Marie Curie Actions Initial Training Networks Solar Energy to Biomass (SE2B) (Grant 675006-SE2B to R.B and A.P.) and by the Research Projects of National Relevance (PRIN) “HARVEST” (Grant 201795SBA3-004 to L.D.).
Publisher Copyright:
© 2019 National Academy of Sciences. All rights reserved.
PY - 2019/6/4
Y1 - 2019/6/4
N2 - Biological systems are subjected to continuous environmental fluctuations, and therefore, flexibility in the structure and function of their protein building blocks is essential for survival. Protein dynamics are often local conformational changes, which allows multiple dynamical processes to occur simultaneously and rapidly in individual proteins. Experiments often average over these dynamics and their multiplicity, preventing identification of the molecular origin and impact on biological function. Green plants survive under high light by quenching excess energy, and Light-Harvesting Complex Stress Related 1 (LHCSR1) is the protein responsible for quenching in moss. Here, we expand an analysis of the correlation function of the fluorescence lifetime by improving the estimation of the lifetime states and by developing a multicomponent model correlation function, and we apply this analysis at the single-molecule level. Through these advances, we resolve previously hidden rapid dynamics, including multiple parallel processes. By applying this technique to LHCSR1, we identify and quantitate parallel dynamics on hundreds of microseconds and tens of milliseconds timescales, likely at two quenching sites within the protein. These sites are individually controlled in response to fluctuations in sunlight, which provides robust regulation of the light-harvesting machinery. Considering our results in combination with previous structural, spectroscopic, and computational data, we propose specific pigments that serve as the quenching sites. These findings, therefore, provide a mechanistic basis for quenching, illustrating the ability of this method to uncover protein function.
AB - Biological systems are subjected to continuous environmental fluctuations, and therefore, flexibility in the structure and function of their protein building blocks is essential for survival. Protein dynamics are often local conformational changes, which allows multiple dynamical processes to occur simultaneously and rapidly in individual proteins. Experiments often average over these dynamics and their multiplicity, preventing identification of the molecular origin and impact on biological function. Green plants survive under high light by quenching excess energy, and Light-Harvesting Complex Stress Related 1 (LHCSR1) is the protein responsible for quenching in moss. Here, we expand an analysis of the correlation function of the fluorescence lifetime by improving the estimation of the lifetime states and by developing a multicomponent model correlation function, and we apply this analysis at the single-molecule level. Through these advances, we resolve previously hidden rapid dynamics, including multiple parallel processes. By applying this technique to LHCSR1, we identify and quantitate parallel dynamics on hundreds of microseconds and tens of milliseconds timescales, likely at two quenching sites within the protein. These sites are individually controlled in response to fluctuations in sunlight, which provides robust regulation of the light-harvesting machinery. Considering our results in combination with previous structural, spectroscopic, and computational data, we propose specific pigments that serve as the quenching sites. These findings, therefore, provide a mechanistic basis for quenching, illustrating the ability of this method to uncover protein function.
KW - Nonphotochemical quenching
KW - Photosynthetic light harvesting
KW - Protein dynamics
KW - Single-molecule fluorescence spectroscopy
UR - http://www.scopus.com/inward/record.url?scp=85066610823&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85066610823&partnerID=8YFLogxK
U2 - 10.1073/pnas.1821207116
DO - 10.1073/pnas.1821207116
M3 - Article
C2 - 31101718
AN - SCOPUS:85066610823
VL - 166
SP - 11247
EP - 11252
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
SN - 0027-8424
IS - 23
ER -