Ultrafast solvation dynamics at binding and active sites of photolyases

Chih-Wei Chang, Lijun Guo, Ya Ting Kao, Jiang Li, Chuang Tan, Tanping Li, Chaitanya Saxena, Zheyun Liu, Lijuan Wang, Aziz Sancar, Dongping Zhong

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55 Citations (Scopus)

Abstract

Dynamic solvation at binding and active sites is critical to protein recognition and enzyme catalysis. We report here the complete characterization of ultrafast solvation dynamics at the recognition site of photoantenna molecule and at the active site of cofactor/ substrate in enzyme photolyase by examining femtosecond-resolved fluorescence dynamics and the entire emission spectra. With direct use of intrinsic antenna and cofactor chromophores, we observed the local environment relaxation on the time scales from a few picoseconds to nearly a nanosecond. Unlike conventional solvation where the Stokes shift is apparent, we observed obvious spectral shape changes with the minor, small, and large spectral shifts in three function sites. These emission profile changes directly reflect the modulation of chromophore's excited states by locally constrained protein and trapped-water collective motions. Such heterogeneous dynamics continuously tune local configurations to optimize photolyase's function through resonance energy transfer from the antenna to the cofactor for energy efficiency and then electron transfer between the cofactor and the substrate for repair of damaged DNA. Such unusual solvation and synergetic dynamics should be general in function sites of proteins.

Original languageEnglish
Pages (from-to)2914-2919
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume107
Issue number7
DOIs
Publication statusPublished - 2010 Feb 16

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