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Parameterization of a single H-bond in Orange Carotenoid Protein by atomic mutation reveals principles of evolutionary design of complex chemical photosystems
- Source :
- Frontiers in Molecular Biosciences, Vol 10 (2023)
- Publication Year :
- 2023
- Publisher :
- Frontiers Media S.A., 2023.
-
Abstract
- Introduction: Dissecting the intricate networks of covalent and non-covalent interactions that stabilize complex protein structures is notoriously difficult and requires subtle atomic-level exchanges to precisely affect local chemical functionality. The function of the Orange Carotenoid Protein (OCP), a light-driven photoswitch involved in cyanobacterial photoprotection, depends strongly on two H-bonds between the 4-ketolated xanthophyll cofactor and two highly conserved residues in the C-terminal domain (Trp288 and Tyr201).Method: By orthogonal translation, we replaced Trp288 in Synechocystis OCP with 3-benzothienyl-L-alanine (BTA), thereby exchanging the imino nitrogen for a sulphur atom.Results: Although the high-resolution (1.8 Å) crystal structure of the fully photoactive OCP-W288_BTA protein showed perfect isomorphism to the native structure, the spectroscopic and kinetic properties changed distinctly. We accurately parameterized the effects of the absence of a single H-bond on the spectroscopic and thermodynamic properties of OCP photoconversion and reveal general principles underlying the design of photoreceptors by natural evolution.Discussion: Such “molecular surgery” is superior over trial-and-error methods in hypothesis-driven research of complex chemical systems.
Details
- Language :
- English
- ISSN :
- 2296889X
- Volume :
- 10
- Database :
- Directory of Open Access Journals
- Journal :
- Frontiers in Molecular Biosciences
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.6ed6139269b24933818f17479db45d3c
- Document Type :
- article
- Full Text :
- https://doi.org/10.3389/fmolb.2023.1072606