5NU2

Human plasma retinol-binding protein (RBP4) is also a fatty acid-binding protein.

(2018) Biochim Biophys Acta 1863: 458-466

• PubMed: 29414511 Search on PubMed
• DOI: https://doi.org/10.1016/j.bbalip.2018.01.010
• Primary Citation of Related Structures:  
  5NTY, 5NU2, 5NU6, 5NU7, 5NU8, 5NU9, 5NUA, 5NUB


• PubMed Abstract: 
  

  RBP4 (plasma retinol-binding protein) is the 21 kDa transporter of all-trans retinol that circulates in plasma as a moderately tight 1:1 molar complex of the vitamin with the protein. RBP4 is primarily synthesized in the liver but is also produced by adipose tissue and circulates bound to a larger protein, transthyretin, TTR, that serves to increase its molecular mass and thus avoid its elimination by glomerular filtration. This paper reports the high resolution three-dimensional structures of human RBP4 naturally lacking bound retinol purified from plasma, urine and amniotic fluid. In all these crystals we found a fatty acid molecule bound in the hydrophobic ligand-binding site, a result confirmed by mass spectrometry measurements. In addition we also report the 1.5 Å resolution structures of human holo-RBP4 and of the protein saturated with palmitic and lauric acid and discuss the interaction of the fatty acids and retinol with the protein.

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Organizational Affiliation: 

Biocrystallography Laboratory, Department of Biotechnology, University of Verona, Ca Vignal 1, strada Le Grazie 15, 37134 Verona, Italy.