7ZTU

Crystal structure of the carotenoid-binding protein domain from silkworm Bombyx mori (BmCBP) in the apoform, D162L mutant

Summary for 7ZTU

• Entry DOI: 10.2210/pdb7ztu/pdb
• Descriptor: Carotenoid-binding protein (2 entities in total)
• Functional Keywords: carotenoid-binding protein, carotenoid transport, cbp, stard, start domain, bombyx mori, transport protein
• Biological source: Bombyx mori (domestic silkworm)
• Total number of polymer chains: 1
• Total formula weight: 28528.89

Authors

Sluchanko, N.N.,Boyko, K.M.,Varfolomeeva, L.A.,Slonimskiy, Y.B.,Egorkin, N.A.,Maksimov, E.G.,Popov, V.O. (deposition date: 2022-05-11, release date: 2022-10-26, Last modification date: 2024-01-31)

Primary citation

Sluchanko, N.N.,Slonimskiy, Y.B.,Egorkin, N.A.,Varfolomeeva, L.A.,Faletrov, Y.V.,Moysenovich, A.M.,Parshina, E.Y.,Friedrich, T.,Maksimov, E.G.,Boyko, K.M.,Popov, V.O.
Silkworm carotenoprotein as an efficient carotenoid extractor, solubilizer and transporter.
Int.J.Biol.Macromol., 223:1381-1393, 2022

PubMed Abstract: Found in many organisms, water-soluble carotenoproteins are prospective antioxidant nanocarriers for biomedical applications. Yet, the toolkit of characterized carotenoproteins is rather limited: such proteins are either too specific binders of only few different carotenoids, or their ability to transfer carotenoids to various acceptor systems is unknown. Here, by focusing on a recently characterized recombinant ~27-kDa Carotenoid-Binding Protein from Bombyx mori (BmCBP) [Slonimskiy et al., International Journal of Biological Macromolecules 214 (2022): 664-671], we analyze its carotenoid-binding repertoire and potential as a carotenoid delivery module. We show that BmCBP forms productive complexes with both hydroxyl- and ketocarotenoids - lutein, zeaxanthin, astaxanthin, canthaxanthin and a smaller antioxidant, aporhodoxanthinone, but not with β-carotene or retinal, which defines its broad ligand specificity toward xanthophylls valuable to human health. Moreover, the His-tagged BmCBP apoform is capable of cost-efficient and scalable enrichment of xanthophylls from various crude methanolic herbal extracts. Upon carotenoid binding, BmCBP remains monomeric and shows a remarkable ability to dynamically shuttle carotenoids to biological membrane models and to unrelated carotenoproteins, which in particular makes from the cyanobacterial Orange Carotenoid Protein a blue-light controlled photoswitch. Furthermore, administration of BmCBP loaded by zeaxanthin stimulates fibroblast growth, which is attractive for cell- and tissue-based assays.

PubMed: 36395947
DOI: 10.1016/j.ijbiomac.2022.11.093

Experimental method

X-RAY DIFFRACTION (1.9 Å)