1HK1

HUMAN SERUM ALBUMIN COMPLEXED WITH THYROXINE (3,3',5,5'-TETRAIODO-L-THYRONINE)


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.65 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.200 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Structural Basis of Albumin-Thyroxine Interactions and Familial Dysalbuminemic Hyperthyroxinemia

Petitpas, I.Petersen, C.E.Ha, C.E.Bhattacharya, A.A.Zunszain, P.A.Ghuman, J.Bhagavan, N.V.Curry, S.

(2003) Proc.Natl.Acad.Sci.USA 100: 6440

  • DOI: 10.1073/pnas.1137188100
  • Primary Citation of Related Structures:  

  • PubMed Abstract: 
  • Human serum albumin (HSA) is the major protein component of blood plasma and serves as a transporter for thyroxine and other hydrophobic compounds such as fatty acids and bilirubin. We report here a structural characterization of HSA-thyroxine intera ...

    Human serum albumin (HSA) is the major protein component of blood plasma and serves as a transporter for thyroxine and other hydrophobic compounds such as fatty acids and bilirubin. We report here a structural characterization of HSA-thyroxine interactions. Using crystallographic analyses we have identified four binding sites for thyroxine on HSA distributed in subdomains IIA, IIIA, and IIIB. Mutation of residue R218 within subdomain IIA greatly enhances the affinity for thyroxine and causes the elevated serum thyroxine levels associated with familial dysalbuminemic hyperthyroxinemia (FDH). Structural analysis of two FDH mutants of HSA (R218H and R218P) shows that this effect arises because substitution of R218, which contacts the hormone bound in subdomain IIA, produces localized conformational changes to relax steric restrictions on thyroxine binding at this site. We have also found that, although fatty acid binding competes with thyroxine at all four sites, it induces conformational changes that create a fifth hormone-binding site in the cleft between domains I and III, at least 9 A from R218. These structural observations are consistent with binding data showing that HSA retains a high-affinity site for thyroxine in the presence of excess fatty acid that is insensitive to FDH mutations.


    Organizational Affiliation

    Biophysics Section, Department of Biological Sciences, Imperial College London, South Kensington Campus, United Kingdom.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
SERUM ALBUMIN
A
585Homo sapiensMutation(s): 0 
Gene Names: ALB
Find proteins for P02768 (Homo sapiens)
Go to Gene View: ALB
Go to UniProtKB:  P02768
Small Molecules
Ligands 1 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
T44
Query on T44

Download SDF File 
Download CCD File 
A
3,5,3',5'-TETRAIODO-L-THYRONINE
C15 H11 I4 N O4
XUIIKFGFIJCVMT-LBPRGKRZSA-N
 Ligand Interaction
External Ligand Annotations 
IDBinding Affinity (Sequence Identity %)
T44Kd: 2300 nM PDBBIND
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.65 Å
  • R-Value Free: 0.252 
  • R-Value Work: 0.200 
  • Space Group: P 1 21 1
Unit Cell:
Length (Å)Angle (°)
a = 59.140α = 90.00
b = 88.570β = 102.39
c = 59.820γ = 90.00
Software Package:
Software NamePurpose
CCP4data scaling
CNSrefinement
X-PLORphasing
MOSFLMdata reduction

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2003-05-16
    Type: Initial release
  • Version 1.1: 2011-05-08
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance