Expanding the Repertoire of Photoswitchable Unnatural Amino Acids for Enzyme Engineering

C Caroline Hiefinger (Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg Universitätsstraße 31 D‐93053 Regensburg Germany) M Michela Marcon (Institute of Organic Chemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany) V Verena Pape (Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany) G Guillem Casadevall (Institut de Química Computacional i Catàlisi and Departament de Química Universitat de Girona c/ Maria Aurèlia Capmany 69 Girona 17003 Spain) R Ranit Lahmy (Institute of Organic Chemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany) C Christoph Haag (Institute of Organic Chemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany) J Julian Nazet (Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany) M Michael Bartl (Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany) A Astrid Bruckmann (Institute of Biochemistry Genetics and Microbiology University of Regensburg Universitatsstrasse 31 D‐93053 Regensburg Germany) S Sílvia Osuna B Burkhard König A Andrea Hupfeld (Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg Universitätsstraße 31 D‐93053 Regensburg Germany)

Abstract

Abstract Photoswitchable unnatural amino acids (psUAAs) play a crucial role in the engineering of light‐sensitivity in enzymes, which holds significant promise for diverse applications such as biotherapy and biocatalysis. Besides near‐quantitative photoconversion, the success and expediency of a psUAA for a certain application is defined by its interaction potential with the enzyme, its thermal stability and its effective wavelength of irradiation. To establish high versatility in the current repertoire, we have designed and synthesized six psUAAs based on azobenzene, arylazopyrazole, arylazothiazole, hemithioindigo and spiropyran photoswitches. The resulting psUAAs exhibit an enhanced interaction potential within an enzyme owing to their capacity for hydrogen bonding, ionic interactions and metal ion coordination. Moreover, we observed diverse photochemical behaviors among the psUAAs, with four of them reversibly switching between the isomers with purely visible light. Notably, we identified orthogonal aminoacyl‐tRNA synthetases that facilitate the incorporation of five of the six psUAAs co‐translationally and computationally analyzed the synthetase‐psUAA interactions. Finally, we evaluated the photochemical behavior of the five psUAAs within an enzymatic model and tested the photocontrol of catalysis confirming their diversity. Ultimately, our findings significantly expanded the repertoire of psUAAs and demonstrated their feasibility for enzyme engineering studies.

Article Details

Volume / Issue Vol. 64, Issue 38
Published September 15, 2025
ISSN 1433-7851
Publisher Wiley

Journal Info

Angewandte Chemie International Edition

Wiley

ISSN: 1433-7851 Physical Sciences

Authors (12)

C

Caroline Hiefinger

Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg Universitätsstraße 31 D‐93053 Regensburg Germany

M

Michela Marcon

Institute of Organic Chemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany

V

Verena Pape

Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany

G

Guillem Casadevall

Institut de Química Computacional i Catàlisi and Departament de Química Universitat de Girona c/ Maria Aurèlia Capmany 69 Girona 17003 Spain

R

Ranit Lahmy

Institute of Organic Chemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany

C

Christoph Haag

Institute of Organic Chemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany

J

Julian Nazet

Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany

M

Michael Bartl

Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg, Universitätsstraße 31 D‐93053 Regensburg Germany

A

Astrid Bruckmann

Institute of Biochemistry Genetics and Microbiology University of Regensburg Universitatsstrasse 31 D‐93053 Regensburg Germany

S

Sílvia Osuna

B

Burkhard König

A

Andrea Hupfeld

Institute of Biophysics and Physical Biochemistry and Regensburg Center for Biochemistry University of Regensburg Universitätsstraße 31 D‐93053 Regensburg Germany