Crystal Structure of Retinol-Binding Protein 4 (RBP4) in complex with non-retinoid ligand

Experimental Data Snapshot

  • Resolution: 2.90 Å
  • R-Value Free: 0.286 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.226 

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Identification and Characterization of a Non-retinoid Ligand for Retinol-binding Protein 4 Which Lowers Serum Retinol-binding Protein 4 Levels in Vivo.

Motani, A.Wang, Z.Conn, M.Siegler, K.Zhang, Y.Liu, Q.Johnstone, S.Xu, H.Thibault, S.Wang, Y.Fan, P.Connors, R.Le, H.Xu, G.Walker, N.Shan, B.Coward, P.

(2009) J Biol Chem 284: 7673-7680

  • DOI: https://doi.org/10.1074/jbc.M809654200
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 

    Retinol-binding protein 4 (RBP4) transports retinol from the liver to extrahepatic tissues, and RBP4 lowering is reported to improve insulin sensitivity in mice. We have identified A1120, a high affinity (K(i) = 8.3 nm) non-retinoid ligand for RBP4, which disrupts the interaction between RBP4 and its binding partner transthyretin. Analysis of the RBP4-A1120 co-crystal structure reveals that A1120 induces critical conformational changes at the RBP4-transthyretin interface. Administration of A1120 to mice lowers serum RBP4 and retinol levels but, unexpectedly, does not improve insulin sensitivity. In addition, we show that Rpb4(-/-) mice display normal insulin sensitivity and are not protected from high fat diet-induced insulin resistance. We conclude that lowering RBP4 levels does not improve insulin sensitivity in mice. Therefore, RBP4 lowering may not be an effective strategy for treating diabetes.

  • Organizational Affiliation

    Department of Metabolic Disorders, Amgen, Inc., South San Francisco, California 94080, USA.

Find similar proteins by:  (by identity cutoff)  |  3D Structure
Entity ID: 1
MoleculeChains Sequence LengthOrganismDetailsImage
Retinol-binding protein 4
A, B
212Homo sapiensMutation(s): 0 
Gene Names: RBP4PRO2222
UniProt & NIH Common Fund Data Resources
Find proteins for P02753 (Homo sapiens)
Explore P02753 
Go to UniProtKB:  P02753
PHAROS:  P02753
Entity Groups  
Sequence Clusters30% Identity50% Identity70% Identity90% Identity95% Identity100% Identity
UniProt GroupP02753
Sequence Annotations
  • Reference Sequence
Small Molecules
Ligands 1 Unique
IDChains Name / Formula / InChI Key2D Diagram3D Interactions
Query on 2T1

Download Ideal Coordinates CCD File 
C [auth A],
D [auth B]
2-[({4-[2-(trifluoromethyl)phenyl]piperidin-1-yl}carbonyl)amino]benzoic acid
C20 H19 F3 N2 O3
Binding Affinity Annotations 
IDSourceBinding Affinity
2T1 PDBBind:  3FMZ Ki: 8.3 (nM) from 1 assay(s)
BindingDB:  3FMZ IC50: min: 0.16, max: 122 (nM) from 5 assay(s)
Experimental Data & Validation

Experimental Data

  • Resolution: 2.90 Å
  • R-Value Free: 0.286 
  • R-Value Work: 0.223 
  • R-Value Observed: 0.226 
  • Space Group: P 65
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 84.802α = 90
b = 84.802β = 90
c = 119.557γ = 120
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
PDB_EXTRACTdata extraction
ADSCdata collection

Structure Validation

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Entry History 

Deposition Data

Revision History  (Full details and data files)

  • Version 1.0: 2009-01-27
    Type: Initial release
  • Version 1.1: 2011-07-13
    Changes: Version format compliance