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Photophysics of the red chromophore of HcRed: evidence for cis-trans isomerization and protonation-state changes.
J Phys Chem B. 2010 Apr 08; 114(13):4678-85.JP

Abstract

HcRed is a dimeric intrinsically fluorescent protein with origins in the sea anemone Heteractis crispa. This protein exhibits deep red absorption and emission properties. Using a combination of ensemble and single molecule methods and by varying environmental parameters such as temperature and pH, we found spectroscopic evidence for the presence of two ground state conformers, trans and cis chromophores that are in thermal equilibrium and that follow different excited-state pathways upon exposure to light. The photocycle of HcRed appears to be a combination of both kindling proteins and bright emitting GFP/GFP-like proteins: the trans chromophore undergoes light driven isomerization followed by radiative relaxation with a fluorescence lifetime of 0.5 ns. The cis chromophore exhibits a photocycle similar to bright GFPs and GFP-like proteins such as enhanced GFP, enhanced YFP or DsRed, with radiative relaxation with a fluorescence lifetime of 1.5 ns, singlet-triplet deactivation on a microsecond time scale and solvent controlled protonation/deprotonation in tens of microseconds. Using single molecule spectroscopy, we identify trans and cis conformers at the level of individual moieties and show that it is possible that the two conformers can coexist in a single protein due to the dimeric nature of HcRed.

Authors+Show Affiliations

Center for Functional Nanomaterials, Brookhaven National Laboratory, Mail Stop 735, Upton New York 11973, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, Non-P.H.S.

Language

eng

PubMed ID

20230057

Citation

Mudalige, Kumara, et al. "Photophysics of the Red Chromophore of HcRed: Evidence for Cis-trans Isomerization and Protonation-state Changes." The Journal of Physical Chemistry. B, vol. 114, no. 13, 2010, pp. 4678-85.
Mudalige K, Habuchi S, Goodwin PM, et al. Photophysics of the red chromophore of HcRed: evidence for cis-trans isomerization and protonation-state changes. J Phys Chem B. 2010;114(13):4678-85.
Mudalige, K., Habuchi, S., Goodwin, P. M., Pai, R. K., De Schryver, F., & Cotlet, M. (2010). Photophysics of the red chromophore of HcRed: evidence for cis-trans isomerization and protonation-state changes. The Journal of Physical Chemistry. B, 114(13), 4678-85. https://doi.org/10.1021/jp9102146
Mudalige K, et al. Photophysics of the Red Chromophore of HcRed: Evidence for Cis-trans Isomerization and Protonation-state Changes. J Phys Chem B. 2010 Apr 8;114(13):4678-85. PubMed PMID: 20230057.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Photophysics of the red chromophore of HcRed: evidence for cis-trans isomerization and protonation-state changes. AU - Mudalige,Kumara, AU - Habuchi,Satoshi, AU - Goodwin,Peter M, AU - Pai,Ranjith K, AU - De Schryver,Frans, AU - Cotlet,Mircea, PY - 2010/3/17/entrez PY - 2010/3/17/pubmed PY - 2010/6/24/medline SP - 4678 EP - 85 JF - The journal of physical chemistry. B JO - J Phys Chem B VL - 114 IS - 13 N2 - HcRed is a dimeric intrinsically fluorescent protein with origins in the sea anemone Heteractis crispa. This protein exhibits deep red absorption and emission properties. Using a combination of ensemble and single molecule methods and by varying environmental parameters such as temperature and pH, we found spectroscopic evidence for the presence of two ground state conformers, trans and cis chromophores that are in thermal equilibrium and that follow different excited-state pathways upon exposure to light. The photocycle of HcRed appears to be a combination of both kindling proteins and bright emitting GFP/GFP-like proteins: the trans chromophore undergoes light driven isomerization followed by radiative relaxation with a fluorescence lifetime of 0.5 ns. The cis chromophore exhibits a photocycle similar to bright GFPs and GFP-like proteins such as enhanced GFP, enhanced YFP or DsRed, with radiative relaxation with a fluorescence lifetime of 1.5 ns, singlet-triplet deactivation on a microsecond time scale and solvent controlled protonation/deprotonation in tens of microseconds. Using single molecule spectroscopy, we identify trans and cis conformers at the level of individual moieties and show that it is possible that the two conformers can coexist in a single protein due to the dimeric nature of HcRed. SN - 1520-5207 UR - https://www.unboundmedicine.com/medline/citation/20230057/Photophysics_of_the_red_chromophore_of_HcRed:_evidence_for_cis_trans_isomerization_and_protonation_state_changes_ L2 - https://dx.doi.org/10.1021/jp9102146 DB - PRIME DP - Unbound Medicine ER -