6PY0

Crystal Structure of mouse Serum Amyloid A3 (SAA3) bound with Retinol


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.204 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.218 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Molecular basis for retinol binding by serum amyloid A during infection.

Hu, Z.Bang, Y.J.Ruhn, K.A.Hooper, L.V.

(2019) Proc.Natl.Acad.Sci.USA 116: 19077-19082

  • DOI: 10.1073/pnas.1910713116
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Serum amyloid A (SAA) proteins are strongly induced in the liver by systemic infection and in the intestine by bacterial colonization. In infected mice, SAA proteins circulate in association with the vitamin A derivative retinol, suggesting that SAAs ...

    Serum amyloid A (SAA) proteins are strongly induced in the liver by systemic infection and in the intestine by bacterial colonization. In infected mice, SAA proteins circulate in association with the vitamin A derivative retinol, suggesting that SAAs transport retinol during infection. Here we illuminate a structural basis for the retinol-SAA interaction. In the bloodstream of infected mice, most SAA is complexed with high-density lipoprotein (HDL). However, we found that the majority of the circulating retinol was associated with the small fraction of SAA proteins that circulate without binding to HDL, thus identifying free SAA as the predominant retinol-binding form in vivo. We then determined the crystal structure of retinol-bound mouse SAA3 at a resolution of 2.2 Å. Retinol-bound SAA3 formed a novel asymmetric trimeric assembly that was generated by the hydrophobic packing of the conserved amphipathic helices α1 and α3. This hydrophobic packing created a retinol-binding pocket in the center of the trimer, which was confirmed by mutagenesis studies. Together, these findings illuminate the molecular basis for retinol transport by SAA proteins during infection.


    Organizational Affiliation

    Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390.,Howard Hughes Medical Institute, University of Texas Southwestern Medical Center, Dallas, TX 75390.,Department of Immunology, University of Texas Southwestern Medical Center, Dallas, TX 75390; Zehan.Hu@utsouthwestern.edu Lora.Hooper@utsouthwestern.edu.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Serum amyloid A-3 protein
A, B, C
104Mus musculusMutation(s): 0 
Gene Names: Saa3
Find proteins for P04918 (Mus musculus)
Go to UniProtKB:  P04918
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
RTL
Query on RTL

Download SDF File 
Download CCD File 
C
RETINOL
C20 H30 O
FPIPGXGPPPQFEQ-OVSJKPMPSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.204 Å
  • R-Value Free: 0.249 
  • R-Value Work: 0.218 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 53.242α = 90.00
b = 75.749β = 90.00
c = 89.263γ = 90.00
Software Package:
Software NamePurpose
PHASERphasing
HKL-3000data reduction
HKL-3000data scaling
PHENIXrefinement
PDB_EXTRACTdata extraction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

  • Deposited Date: 2019-07-28 
  • Released Date: 2019-08-28 
  • Deposition Author(s): Hu, Z., Hooper, L.V.

Revision History 

  • Version 1.0: 2019-08-28
    Type: Initial release
  • Version 1.1: 2019-09-04
    Type: Data collection, Database references
  • Version 1.2: 2019-09-18
    Type: Data collection, Database references
  • Version 1.3: 2019-10-02
    Type: Data collection, Database references