Origin of the multi-phasic quenching dynamics in the BLUF domains across the species

Yalin Zhou; Siwei Tang; Zijing Chen; Zhongneng Zhou; Jiulong Huang; Xiu-Wen Kang; Shuhua Zou; Bingyao Wang; Tianyi Zhang; Bei Ding; Dongping Zhong

doi:10.1038/s41467-023-44565-5

Origin of the multi-phasic quenching dynamics in the BLUF domains across the species

Nat Commun. 2024 Jan 20;15(1):623. doi: 10.1038/s41467-023-44565-5.

Authors

Yalin Zhou^#¹, Siwei Tang^#¹, Zijing Chen¹, Zhongneng Zhou¹, Jiulong Huang¹, Xiu-Wen Kang¹, Shuhua Zou¹, Bingyao Wang¹, Tianyi Zhang¹, Bei Ding², Dongping Zhong^{3

4}

Affiliations

¹ Center for Ultrafast Science and Technology, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China.
² Center for Ultrafast Science and Technology, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China. bei.ding@sjtu.edu.cn.
³ Center for Ultrafast Science and Technology, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, Shanghai, 200240, China. zhong.28@osu.edu.
⁴ Department of Physics, Department of Chemistry and Biochemistry, and Programs of Biophysics, Chemical Physics, and Biochemistry, The Ohio State University, Columbus, OH, 43210, USA. zhong.28@osu.edu.

^# Contributed equally.

Abstract

Blue light using flavin (BLUF) photoreceptors respond to light via one of nature's smallest photo-switching domains. Upon photo-activation, the flavin cofactor in the BLUF domain exhibits multi-phasic dynamics, quenched by a proton-coupled electron transfer reaction involving the conserved Tyr and Gln. The dynamic behavior varies drastically across different species, the origin of which remains controversial. Here, we incorporate site-specific fluorinated Trp into three BLUF proteins, i.e., AppA, OaPAC and SyPixD, and characterize the percentages for the W_out, W_inNH_in and W_inNH_out conformations using ¹⁹F nuclear magnetic resonance spectroscopy. Using femtosecond spectroscopy, we identify that one key W_inNH_in conformation can introduce a branching one-step proton transfer in AppA and a two-step proton transfer in OaPAC and SyPixD. Correlating the flavin quenching dynamics with the active-site structural heterogeneity, we conclude that the quenching rate is determined by the percentage of W_inNH_in, which encodes a Tyr-Gln configuration that is not conducive to proton transfer.

MeSH terms

Bacterial Proteins / metabolism
Electron Transport
Flavins / chemistry
Light*
Molecular Conformation
Protons*

Substances

Protons
Flavins
Bacterial Proteins

Abstract

MeSH terms

Substances

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