In this study, we exhibited an amino acid (arginine and threonine) derivative Schiff base copper(II) complexes incorporating an azobenzene moiety as a photoresponsive site and conjugated it to egg white lysozyme, a well-known protein, to change ligand conformation under binding to lysozyme. Among several spectroscopic investigations, ESR clearly showed that the nitrogen atom of the amino acid residue of lysozyme was bound to the paramagnetic copper(II) ion of the complex, and UV light irradiation confirmed photoisomerization of the azobenzene moiety of the ligand to cis-form. The binding mode was considered by means of spectroscopic as well as computational methods, whereas complete crystallographic verification was still a preliminary stage.
References
[1]
Andreini, C., Bertini, I., Cavallaro, G.L. and Thornton, J.M. (2008) Metal Ions in Biological Catalysis: From Enzyme Databases to General Principles. Journal of Biological Inorganic Chemistry, 13, 1205-1218. https://doi.org/10.1007/s00775-008-0404-5
[2]
Stappen, C.V., Deng, Y., Liu, Y., Heidari, H., Wang, J.-X., Zhou, Y., Ledray, A.P. and Lu, Y. (2022) Designing Artificial Metalloenzymes by Tuning of the Environment beyond the Primary Coordination Sphere. Chemical Reviews, 122, 11974-12045. https://doi.org/10.1021/acs.chemrev.2c00106
[3]
Dabis, H.J. and Ward, T.R. (2019) Artificial Metalloenzymes: Challenges and Opportunities. ACS Central Science, 5, 1120-1136. https://doi.org/10.1021/acscentsci.9b00397
[4]
Gandin, V., Porchia, M., Tisato, F., Zanella, A, Severin, E., Dolmella, A. and Marzano, C (2013) Novel Mixed-Ligand Copper(I) Complexes: Role of Diimine Ligands on Cytotoxicity and Genotoxicity. Journal of Medicinal Chemistry, 56, 7416-7430. https://doi.org/10.1021/jm400965m
[5]
Nishihara, H. (2005) Combination of Redox- and Photochemistry of Azo-Conjugated Metal Complexes. Coordination Chemistry Reviews, 249, 1468-1475. https://doi.org/10.1016/j.ccr.2004.11.009
[6]
Kashiwagi, K., Tassinari, F., Haraguchi, T., Banerjee-Gosh, K., Akitsu, T. and Naaman, R. (2020) Electron Transfer via Helical Oligopeptide to Laccase Including Chiral Schiff Base Copper Mediators. Symmetry, 12, Article 808. https://doi.org/10.3390/sym12050808
