Biochemical and spectroscopic studies of human melanotransferrin (MTf): electron-paramagnetic resonance evidence for a difference between the iron-binding site of MTf and other transferrins

2.50
Hdl Handle:
http://hdl.handle.net/10547/593439
Title:
Biochemical and spectroscopic studies of human melanotransferrin (MTf): electron-paramagnetic resonance evidence for a difference between the iron-binding site of MTf and other transferrins
Authors:
Farnaud, Sébastien; Amini, Maryam; Rapisarda, Chiara; Cammack, Richard; Bui, Tam; Drake, Alex; Evans, Robert W.; Rahmanto, Yohan Suryo; Richardson, Des R.
Abstract:
Melanotransferrin (MTf) is a member of the transferrin (Tf) family of iron (Fe)-binding proteins that was first identified as a cell-surface marker of melanoma. Although MTf has a high-affinity Fe-binding site that is practically identical to that of serum Tf, the protein does not play an essential role in Fe homeostasis and its precise molecular function remains unclear. A Zn(II)-binding motif, distinct from the Fe-binding site, has been proposed in human MTf based on computer modelling studies. However, little is known concerning the interaction of its proposed binding site(s) with metals and the consequences in terms of MTf conformation. For the first time, biochemical and spectroscopic techniques have been used in this study to characterise metal ion-binding to recombinant MTf. Initially, the binding of Fe to MTf was examined using 6 M urea gel electrophoresis. Although four different iron-loaded forms were observed with serum Tf, only two forms were found with MTf, the apo-form and the N-monoferric holo-protein, suggesting a single high-affinity site. The presence of a single Fe(III)-binding site was also supported by EPR results which indicated that the Fe(III)-binding characteristics of MTf were unique, but somewhat comparable to the N-lobes of human serum Tf and chicken ovo-Tf. Circular dichroism (CD) analysis indicated that, as for Tf, no changes in secondary structure could be observed upon Fe(III)-binding. The ability of MTf to bind Zn(II) was also investigated using CD which demonstrated that the single high-affinity Fe-binding site was distinct from a potential Zn(II)-binding site.
Affiliation:
University of Westminster; King's College London; Brunel University; University of Sydney
Citation:
Farnaud, S., Amini, M., Rapisarda, C., Cammack, R., Bui, T., Drake., A., Evans, R., Rahmanto, Y., Richardson, D. (2008) 'Biochemical and spectroscopic studies of human melanotransferrin (MTf): Electron-paramagnetic resonance evidence for a difference between the iron-binding site of MTf and other transferrins' The International Journal of Biochemistry & Cell Biology 40 (12):2739
Publisher:
Elsevier
Journal:
The International Journal of Biochemistry & Cell Biology
Issue Date:
Jan-2008
URI:
http://hdl.handle.net/10547/593439
DOI:
10.1016/j.biocel.2008.07.003
Additional Links:
http://linkinghub.elsevier.com/retrieve/pii/S1357272508003038
Type:
Article
Language:
en
ISSN:
1357-2725
Appears in Collections:
IHR Institute for Health Research

Full metadata record

DC FieldValue Language
dc.contributor.authorFarnaud, Sébastienen
dc.contributor.authorAmini, Maryamen
dc.contributor.authorRapisarda, Chiaraen
dc.contributor.authorCammack, Richarden
dc.contributor.authorBui, Tamen
dc.contributor.authorDrake, Alexen
dc.contributor.authorEvans, Robert W.en
dc.contributor.authorRahmanto, Yohan Suryoen
dc.contributor.authorRichardson, Des R.en
dc.date.accessioned2016-01-14T11:16:12Zen
dc.date.available2016-01-14T11:16:12Zen
dc.date.issued2008-01en
dc.identifier.citationFarnaud, S., Amini, M., Rapisarda, C., Cammack, R., Bui, T., Drake., A., Evans, R., Rahmanto, Y., Richardson, D. (2008) 'Biochemical and spectroscopic studies of human melanotransferrin (MTf): Electron-paramagnetic resonance evidence for a difference between the iron-binding site of MTf and other transferrins' The International Journal of Biochemistry & Cell Biology 40 (12):2739en
dc.identifier.issn1357-2725en
dc.identifier.doi10.1016/j.biocel.2008.07.003en
dc.identifier.urihttp://hdl.handle.net/10547/593439en
dc.description.abstractMelanotransferrin (MTf) is a member of the transferrin (Tf) family of iron (Fe)-binding proteins that was first identified as a cell-surface marker of melanoma. Although MTf has a high-affinity Fe-binding site that is practically identical to that of serum Tf, the protein does not play an essential role in Fe homeostasis and its precise molecular function remains unclear. A Zn(II)-binding motif, distinct from the Fe-binding site, has been proposed in human MTf based on computer modelling studies. However, little is known concerning the interaction of its proposed binding site(s) with metals and the consequences in terms of MTf conformation. For the first time, biochemical and spectroscopic techniques have been used in this study to characterise metal ion-binding to recombinant MTf. Initially, the binding of Fe to MTf was examined using 6 M urea gel electrophoresis. Although four different iron-loaded forms were observed with serum Tf, only two forms were found with MTf, the apo-form and the N-monoferric holo-protein, suggesting a single high-affinity site. The presence of a single Fe(III)-binding site was also supported by EPR results which indicated that the Fe(III)-binding characteristics of MTf were unique, but somewhat comparable to the N-lobes of human serum Tf and chicken ovo-Tf. Circular dichroism (CD) analysis indicated that, as for Tf, no changes in secondary structure could be observed upon Fe(III)-binding. The ability of MTf to bind Zn(II) was also investigated using CD which demonstrated that the single high-affinity Fe-binding site was distinct from a potential Zn(II)-binding site.en
dc.language.isoenen
dc.publisherElsevieren
dc.relation.urlhttp://linkinghub.elsevier.com/retrieve/pii/S1357272508003038en
dc.rightsArchived with thanks to The International Journal of Biochemistry & Cell Biologyen
dc.subjectmelanotransferrinen
dc.subjecttransferrinen
dc.subjectironen
dc.subjectelectron-paramagnetic resonance spectroscopyen
dc.subjectcircular dichroism (CD)en
dc.titleBiochemical and spectroscopic studies of human melanotransferrin (MTf): electron-paramagnetic resonance evidence for a difference between the iron-binding site of MTf and other transferrinsen
dc.typeArticleen
dc.contributor.departmentUniversity of Westminsteren
dc.contributor.departmentKing's College Londonen
dc.contributor.departmentBrunel Universityen
dc.contributor.departmentUniversity of Sydneyen
dc.identifier.journalThe International Journal of Biochemistry & Cell Biologyen
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