5DYH

Ti(IV) bound human serum transferrin


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.68 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 

wwPDB Validation   3D Report Full Report


This is version 1.4 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
  • Primary Citation of Related Structures:  
    5DYH

  • 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

    VA Caribbean Healthcare System, 10 Casia Street, San Juan, Puerto Rico 00921.



Macromolecules
Find similar proteins by:  (by identity cutoff)  |  Structure
Entity ID: 1
MoleculeChainsSequence LengthOrganismDetailsImage
SerotransferrinAB698Homo sapiensMutation(s): 0 
Gene Names: TFPRO1400
Find proteins for P02787 (Homo sapiens)
Explore P02787 
Go to UniProtKB:  P02787
NIH Common Fund Data Resources
PHAROS  P02787
Protein Feature View
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  • Reference Sequence
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.68 Å
  • R-Value Free: 0.237 
  • R-Value Work: 0.202 
  • R-Value Observed: 0.204 
  • Space Group: P 21 21 21
Unit Cell:
Length ( Å )Angle ( ˚ )
a = 88.275α = 90
b = 102.016β = 90
c = 197.899γ = 90
Software Package:
Software NamePurpose
PHENIXrefinement
HKL-2000data collection
HKL-2000data scaling
PDB_EXTRACTdata extraction
PHASERphasing
HKL-2000data reduction

Structure Validation

View Full Validation Report



Entry History & Funding Information

Deposition Data


Funding OrganizationLocationGrant Number
National Institutes of Health/National Cancer Institute (NIH/NCI)United 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
    Changes: Database references
  • Version 1.2: 2016-05-18
    Changes: Database references
  • Version 1.3: 2017-09-20
    Changes: Author supporting evidence, Derived calculations
  • Version 1.4: 2019-12-04
    Changes: Author supporting evidence