8C18

Solution structure of carotenoid-binding protein AstaPo1 in complex with astaxanthin

Summary for 8C18

• Entry DOI: 10.2210/pdb8c18/pdb
• NMR Information: BMRB: 34781
• Descriptor: Astaxanthin binding fasciclin family protein, ASTAXANTHIN (2 entities in total)
• Functional Keywords: protein, transport protein, astaxanthin, carotenoid
• Biological source: Coelastrella astaxanthina
• Total number of polymer chains: 1
• Total formula weight: 22230.98

Authors

Kornilov, F.D.,Savitskaya, A.G.,Slonimskiy, Y.B.,Goncharuk, S.A.,Sluchanko, N.N.,Mineev, K.S. (deposition date: 2022-12-20, release date: 2023-04-05, Last modification date: 2024-06-19)

Primary citation

Kornilov, F.D.,Slonimskiy, Y.B.,Lunegova, D.A.,Egorkin, N.A.,Savitskaya, A.G.,Kleymenov, S.Y.,Maksimov, E.G.,Goncharuk, S.A.,Mineev, K.S.,Sluchanko, N.N.
Structural basis for the ligand promiscuity of the neofunctionalized, carotenoid-binding fasciclin domain protein AstaP.
Commun Biol, 6:471-471, 2023

PubMed Abstract: Fasciclins (FAS1) are ancient adhesion protein domains with no common small ligand binding reported. A unique microalgal FAS1-containing astaxanthin (AXT)-binding protein (AstaP) binds a broad repertoire of carotenoids by a largely unknown mechanism. Here, we explain the ligand promiscuity of AstaP-orange1 (AstaPo1) by determining its NMR structure in complex with AXT and validating this structure by SAXS, calorimetry, optical spectroscopy and mutagenesis. α1-α2 helices of the AstaPo1 FAS1 domain embrace the carotenoid polyene like a jaw, forming a hydrophobic tunnel, too short to cap the AXT β-ionone rings and dictate specificity. AXT-contacting AstaPo1 residues exhibit different conservation in AstaPs with the tentative carotenoid-binding function and in FAS1 proteins generally, which supports the idea of AstaP neofunctionalization within green algae. Intriguingly, a cyanobacterial homolog with a similar domain structure cannot bind carotenoids under identical conditions. These structure-activity relationships provide the first step towards the sequence-based prediction of the carotenoid-binding FAS1 members.

PubMed: 37117801
DOI: 10.1038/s42003-023-04832-z

Experimental method

SOLUTION NMR