5DYH

Ti(IV) bound human serum transferrin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.682 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.202 

wwPDB Validation 3D Report Full Report


This is version 1.3 of the entry. See complete history

Literature

Unusual Synergism of Transferrin and Citrate in the Regulation of Ti(IV) Speciation, Transport, and Toxicity.

Tinoco, A.D.Saxena, M.Sharma, S.Noinaj, N.Delgado, Y.Quinones Gonzalez, E.P.Conklin, S.E.Zambrana, N.Loza-Rosas, S.A.Parks, T.B.

(2016) J.Am.Chem.Soc. 138: 5659-5665

  • DOI: 10.1021/jacs.6b01966

  • PubMed Abstract: 
  • Human serum transferrin (sTf) is a protein that mediates the transport of iron from blood to cells. Assisted by the synergistic anion carbonate, sTf transports Fe(III) by binding the metal ion in a closed conformation. Previous studies suggest sTf's ...

    Human serum transferrin (sTf) is a protein that mediates the transport of iron from blood to cells. Assisted by the synergistic anion carbonate, sTf transports Fe(III) by binding the metal ion in a closed conformation. Previous studies suggest sTf's role as a potential transporter of other metals such as titanium. Ti is a widely used metal in colorants, foods, and implants. A substantial amount of Ti is leached into blood from these implants. However, the fate of the leached Ti and its transport into the cells is not known. Understanding Ti interaction with sTf assumes a greater significance with our ever increasing exposure to Ti in the form of implants. On the basis of in vitro studies, it was speculated that transferrin can bind Ti(IV) assisted by a synergistic anion. However, the role and identity of the synergistic anion(s) and the conformational state in which sTf binds Ti(IV) are not known. Here we have solved the first X-ray crystal structure of a Ti(IV)-bound sTf. We find that sTf binds Ti(IV) in an open conformation with both carbonate and citrate as synergistic anions at the metal binding sites, an unprecedented role for citrate. Studies with cell lines suggest that Ti(IV)-sTf is transported into cells and that sTf and citrate regulate the metal's blood speciation and attenuate its cytotoxic property. Our results provide the first glimpse into the citrate-transferrin synergism in the regulation of Ti(IV) bioactivity and offers insight into the future design of Ti(IV)-based anticancer drugs.


    Organizational Affiliation

    Department of Biological Sciences, Purdue University , 240 S. Martin Jischke Drive, Hockmeyer Hall, West Lafayette, Indiana 47907, United States.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Serotransferrin
A, B
698Homo sapiensMutation(s): 0 
Gene Names: TF
Find proteins for P02787 (Homo sapiens)
Go to Gene View: TF
Go to UniProtKB:  P02787
Small Molecules
Ligands 3 Unique
IDChainsName / Formula / InChI Key2D Diagram3D Interactions
CIT
Query on CIT

Download SDF File 
Download CCD File 
A, B
CITRIC ACID
C6 H8 O7
KRKNYBCHXYNGOX-UHFFFAOYSA-N
 Ligand Interaction
CO3
Query on CO3

Download SDF File 
Download CCD File 
A, B
CARBONATE ION
C O3
BVKZGUZCCUSVTD-UHFFFAOYSA-L
 Ligand Interaction
4TI
Query on 4TI

Download SDF File 
Download CCD File 
A, B
TITANIUM ION
Ti
VEOOXLFYKHRLHJ-UHFFFAOYSA-N
 Ligand Interaction
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.682 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.202 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 88.275α = 90.00
b = 102.016β = 90.00
c = 197.899γ = 90.00
Software Package:
Software NamePurpose
HKL-2000data collection
PDB_EXTRACTdata extraction
PHASERphasing
HKL-2000data reduction
HKL-2000data scaling
PHENIXrefinement

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Cancer InstituteUnited States1SC1CA190504-01
The Puerto Rico Science, Technology, and Research TrustPuerto Rico2013-000019
University of Puerto Rico Score Stabilization GrantPuerto Rico--

Revision History 

  • Version 1.0: 2016-04-27
    Type: Initial release
  • Version 1.1: 2016-05-11
    Type: Database references
  • Version 1.2: 2016-05-18
    Type: Database references
  • Version 1.3: 2017-09-20
    Type: Author supporting evidence, Derived calculations