INFIQC   05475
INSTITUTO DE INVESTIGACIONES EN FISICO- QUIMICA DE CORDOBA
Unidad Ejecutora - UE
artículos
Título:
Binding of [Cr(phen)3]3+ to transferrin at extracellular and endosomal pHs: Potential application in photodynamic therapy
Autor/es:
PABLO F. GARCÍA; J. TONEATTO; M. JAZMÍN SILVERO,; ARGÜELLO, GERARDO ANÍBAL
Revista:
BIOCHIMICA ET BIOPHYSICA ACTA-GENERAL SUBJECTS
Editorial:
ELSEVIER SCIENCE BV
Referencias:
Lugar: Amsterdam; Año: 2014 vol. 1840 p. 2695 - 2701
ISSN:
0304-4165
Resumen:
Background: Transferrin is an iron-binding blood plasma glycoprotein that controls the level of free iron in biological
fluids. This protein has been deeply studied in the past few years because of its potential use as a strategy of
drug targeting to tumor tissues. Chromium complex, [Cr(phen)3]3+ (phen = 1,10-phenanthroline), has been
proposed as photosensitizers for photodynamic therapy (PDT). Thus, we analyzed the binding of chromium
complex, [Cr(phen)3]3+, to transferrin for a potential delivery of this diimine complex to tumor cells for PDT.
Methods: The interaction between [Cr(phen)3]3+ and holotransferrin (holoTf) was studied by fluorescence
quenching technique, circular dichroism (CD) and ultraviolet (UV)?visible spectroscopy.
Results: [Cr(phen)3]3+ binds strongly to holoTfwith a binding constant around 105M−1, that depends on the pH.
The thermodynamic parameters indicated that hydrophobic interactions played amajor role in the binding processes.
The CD studies showed that there are no conformational changes in the secondary and tertiary structures
of the protein.
Conclusions: These results suggest that the binding process would occur in a site different from the specific iron
binding sites of the protein and would be the same in both protein states. As secondary and tertiary structures of
transferrin do not showremarkable changes, we propose that the TfR could recognize the holoTf despite having a
chromium complex associated.
General significance: Understanding the interaction between [Cr(phen)3]3+ with transferrin is relevant because
this protein could be a delivery agent of Cr(III) complex to tumor cells. This can allow us to understand further
the role of Cr(III) complex as sensitizer in PDT.