1. Structural basis of selective beta-carotene binding by a soluble protein.
- Author
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Egorkin NA, Dominnik EE, Raevskii RI, Kuklina DD, Varfolomeeva LA, Popov VO, Boyko KM, and Sluchanko NN
- Subjects
- Crystallography, X-Ray, Animals, Binding Sites, Hydrophobic and Hydrophilic Interactions, Carotenoids chemistry, Carotenoids metabolism, Solubility, Lycopene metabolism, Lycopene chemistry, Protein Multimerization, Xanthophylls metabolism, Xanthophylls chemistry, Male, beta Carotene metabolism, beta Carotene chemistry, Protein Binding, Models, Molecular
- Abstract
β-carotene (BCR) is the most abundant carotenoid, a colorant, antioxidant, and provitamin A. The extreme hydrophobicity of this hydrocarbon requires special mechanisms for distribution in aqueous media, including water-soluble carotenoproteins. However, all known carotenoproteins prefer oxygenated carotenoids and bind BCR inefficiently. Here, we present the crystal structure of the BCR-binding protein (BBP) from gregarious male locusts, which is responsible for their vivid yellow body coloration, in complex with its natural ligand, BCR. BBP forms an antiparallel tubular homodimer with α/β-wrap folded monomers, each forming a hydrophobic 47 Å long, coaxial tunnel that opens outward and is occupied by one s-cis
C6-C7 , all-trans BCR molecule. In the BCR absence, BBP accepts a range of xanthophylls, with reduced efficiency depending on the position and number of oxygen atoms, but rejects lycopene. The structure captures a pigment complex with a Takeout 1 protein and inspires potential applications of BBP as a BCR solubilizer., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 Elsevier Inc. All rights reserved.)- Published
- 2024
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