101. Probing the spectral signatures of orange carotenoid protein by orthogonal translation with aromatic non-canonical amino acids
- Author
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Hsueh-Wei Tseng, Marcus Moldenhauer, Thomas Friedrich, Eugene G. Maksimov, and Nediljko Budisa
- Subjects
Amino Acids, Aromatic ,Bacterial Proteins ,Biophysics ,Cell Biology ,Amino Acids ,Cyanobacteria ,Carotenoids ,Molecular Biology ,Biochemistry - Abstract
Orange Carotenoid Protein (OCP) is a water-soluble photoreceptor involved in photoprotection of cyanobacteria. The photoactive OCP contains a bound ketocarotenoid cofactor held in a protein matrix with a hydrogen bonding network. We have developed a system to replace essential residues of the photoactive OCP with non-canonical aromatic analogues that produce well-defined chemical or steric changes. Preliminary spectroscopic evaluation of the generated OCP variants demonstrates the potential of this "molecular surgery" to disentangle protein-chromophore interaction networks that are critical for photoreceptor function. In this way, the number and strength of key contacts with non-canonical amino acids could be controlled and manipulated. We have illustrated this principle here by replacing hydrogen bond donating residues with aromatic non-canonical amino acids that alter the state preference of OCP.
- Published
- 2022