TY - JOUR
T1 - Dual Time-Scale Proton Transfer and High-Energy, Long-Lived Excitons Unveiled by Broadband Ultrafast Time-Resolved Fluorescence in Adenine-Uracil RNA Duplexes
AU - Chan, Ruth Chau Ting
AU - Ma, Chensheng
AU - Wong, Allen Ka Wa
AU - Chan, Chris Tsz Leung
AU - Chow, Joshua Chiu Lok
AU - Kwok, Wai Ming
N1 - Funding Information:
The authors acknowledge the National Natural Science Foundation of China (Nos. 21773157 and 22073063), the Project of Shenzhen Science and Technology (JCYJ20190808110801662), and the Research Grants Council of Hong Kong (PolyU/153020/17P, PolyU/153023/19P and PolyU/153017/21P) for financial support.
Publisher Copyright:
© 2022 American Chemical Society.
PY - 2022/1/13
Y1 - 2022/1/13
N2 - In contrast to the immense amount of research on electronically excited DNA, surprisingly little has been done about the excited states of RNA. Herein, we demonstrate an ultrafast broadband time-resolved fluorescence and fluorescence anisotropy study to probe directly the intrinsic fluorescence and overall dynamics of the fluorescence from a homopolymeric adenine·uracil RNA duplex adopting the A-form structure. The results unveiled complex deactivation through distinctive multichannels mediated by states of varied energy, a character of charge transfer, and a lifetime from sub-picosecond to nanoseconds. In particular, we observed an unprecedented kinetic isotopic effect and participation of unusual proton transfer from states in two discrete energies and time domains. We also identified a high-energy nanosecond emission that we attributed to its fluorescence anisotropy to long-lived weakly emissive excitons not reported in DNA. These distinguishing features originate from the stacking, pairing, and local hydration environment specific to the A-form conformation of the adenine·uracil double helix.
AB - In contrast to the immense amount of research on electronically excited DNA, surprisingly little has been done about the excited states of RNA. Herein, we demonstrate an ultrafast broadband time-resolved fluorescence and fluorescence anisotropy study to probe directly the intrinsic fluorescence and overall dynamics of the fluorescence from a homopolymeric adenine·uracil RNA duplex adopting the A-form structure. The results unveiled complex deactivation through distinctive multichannels mediated by states of varied energy, a character of charge transfer, and a lifetime from sub-picosecond to nanoseconds. In particular, we observed an unprecedented kinetic isotopic effect and participation of unusual proton transfer from states in two discrete energies and time domains. We also identified a high-energy nanosecond emission that we attributed to its fluorescence anisotropy to long-lived weakly emissive excitons not reported in DNA. These distinguishing features originate from the stacking, pairing, and local hydration environment specific to the A-form conformation of the adenine·uracil double helix.
UR - http://www.scopus.com/inward/record.url?scp=85122760640&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.1c03553
DO - 10.1021/acs.jpclett.1c03553
M3 - Journal article
C2 - 34978832
AN - SCOPUS:85122760640
SN - 1948-7185
VL - 13
SP - 302
EP - 311
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 1
ER -