5i9j

Structure of the cholesterol and lutein-binding domain of human STARD3 at 1.74A

spinqualitylabelsall models 5i9j, resolution 1.74Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5i9j is a 1 chain structure with sequence from Homo sapiens. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.74Å Ligands: EDO, SO4, TLA Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function STAR3_HUMAN Binds and transports cholesterol. Promotes steroidogenesis in placenta and brain. Publication Abstract from PubMed A crystal structure of the lutein-binding domain of human StARD3 (StAR-related lipid-transfer protein 3; also known as MLN64) has been refined to 1.74 A resolution. A previous structure of the same protein determined to 2.2 A resolution highlighted homology with StARD1 and shared cholesterol-binding character. StARD3 has since been recognized as a carotenoid-binding protein in the primate retina, where its biochemical function of binding lutein with specificity appears to be well suited to recruit this photoprotective molecule. The current and previous structures correspond closely to each other (r.m.s.d. of 0.25 A), especially in terms of the helix-grip fold constructed around a solvent-filled cavity. Regions of interest were defined with alternate conformations in the current higher-resolution structure, including Arg351 found within the cavity and Omega1, a loop of four residues found just outside the cavity entrance. Models of the complex with lutein generated by rigid-body docking indicate that one of the ionone rings must protrude outside the cavity, and this insight has implications for molecular interactions with transport proteins and enzymes that act on lutein. Interestingly, models with the -ionone ring characteristic of lutein pointing towards the bottom of the cavity were associated with fewer steric clashes, suggesting that steric complementarity and ligand asymmetry may play a role in discriminating lutein from the other ocular carotenoids zeaxanthin and meso-zeaxanthin, which only have beta-ionone rings. Structure of the lutein-binding domain of human StARD3 at 1.74 A resolution and model of a complex with lutein.,Horvath MP, George EW, Tran QT, Baumgardner K, Zharov G, Lee S, Sharifzadeh H, Shihab S, Mattinson T, Li B, Bernstein PS Acta Crystallogr F Struct Biol Commun. 2016 Aug;72(Pt 8):609-18. doi:, 10.1107/S2053230X16010694. Epub 2016 Jul 27. PMID:27487925 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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