High resolution crystal structure data of human plasma retinol-binding protein (RBP4) bound to retinol and fatty acids

Retinol is transported in vertebrate plasma bound to a protein called retinol-binding protein (RBP4) so far believed to be specific for the vitamin. When the protein is saturated with retinol it binds tightly to another plasma protein, transthyretin while when not saturated with retinol it does not bind to TTR (Goodman, 1984). The X-ray structures of human RBP4, holo and devoid of retinol in its binding site are known to resolutions of 2.0 and 2.5 Å (Cowan et al., 1990; Zanotti et al., 1993) [2], [3]. We have shown that RBP4 is not specific for retinol but it is also found in plasma, urine and amniotic fluid bound to fatty acids. Here we present 1.5 Å resolution crystal data on human plasma retinol-binding protein bound to retinol and fatty acids. These are the highest resolution data available in the Protein Data Bank for this protein. For further details and experimental findings please refer to the article “ Human plasma retinol-binding protein (RBP4) is also a fatty acid-binding protein” (Perduca et al., 2018) [4].