22IY
Crystal structure of the unliganded microalgal AstaP-pink1 carotenoprotein
Summary for 22IY
| Entry DOI | 10.2210/pdb22iy/pdb |
| Descriptor | Astaxanthin-binding pink protein of fasciclin family, GLYCEROL (3 entities in total) |
| Functional Keywords | microalgal protein, carotenoprotein, astap-pink1, unliganded form, astaxanthin-binding pink protein, transport protein |
| Biological source | Scenedesmus sp. Oki-4N |
| Total number of polymer chains | 1 |
| Total formula weight | 20278.82 |
| Authors | Sluchanko, N.N.,Slonimskiy, Y.B.,Varfolomeeva, L.A.,Popov, V.O.,Boyko, K.M. (deposition date: 2026-01-13, release date: 2026-02-04, Last modification date: 2026-02-18) |
| Primary citation | Slonimskiy, Y.B.,Lunegova, D.A.,Nikolaev, A.S.,Matyuta, I.O.,Klementiev, K.E.,Popov, V.O.,Boyko, K.M.,Gushchin, I.Y.,Sluchanko, N.N. Crystal structure and functional characterization of the microalgal carotenoprotein AstaP-pink1. Biochem.Biophys.Res.Commun., 805:153374-153374, 2026 Cited by PubMed Abstract: The recently discovered family of microalgal water-soluble astaxanthin-binding proteins (AstaPs) functions in carotenoid sequestration and transfer. We present the crystal structure and characterization of AstaP-pink1, a homolog from Scenedesmus sp. We show that despite low sequence identity with the known AstaP-orange1, AstaP-pink1 also binds various xanthophylls, but in contrast to AstaP-orange1, induces a pronounced bathochromic shift and a near-UV spectral bump upon binding ketocarotenoids, which is reminiscent of photoactivated Orange Carotenoid Protein (OCP). Mutagenesis and domain-swap experiments indicate that its unique spectral tuning likely results from carotenoid isomerization, forced by the interplay between its N-terminal jaw and body subdomains connected by the hinge loop of different sequence and length. This study attempts to rationalize the spectral and functional diversification of AstaPs and highlights their potential as engineered modules for carotenoid delivery. PubMed: 41637989DOI: 10.1016/j.bbrc.2026.153374 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (1.65 Å) |
Structure validation
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