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Article: Rationalization of the strength of metal binding to human serum transferrin

TitleRationalization of the strength of metal binding to human serum transferrin
Authors
Issue Date1996
PublisherBlackwell Publishing Ltd. The Journal's web site is located at http://www.blackwellpublishing.com/journals/EJB
Citation
European Journal Of Biochemistry, 1996, v. 242 n. 2, p. 387-393 How to Cite?
AbstractA wide range of metal ions of natural, therapeutic, diagnostic and toxic interest are transported by serum transferrin (80 kDa). It is therefore important to understand the factors that control the strength of metal binding. We show here that even though Sc3+ has only slightly larger ionic radius than Fe3+ (0.075 nm versus 0.065 nm), it binds to the C-lobe and N-lobe sites much more weakly: logK1(*) (bicarbonate-independent binding constant) 14.6 ± 0.2, logK2(*) 13.3 ± 0.3, respectively (10 mM Hepes, 5 mM bicarbonate, 310 K). Preferential binding to the C-lobe was established by 1H-NMR spectroscopy. We show that the strength of binding of divalent and trivalent metal ions to human serum transferrin correlates with metal ion acidity [and therefore with the strength of binding to hydroxide, K1(OH)]. The correlations are of predictive value for a range of other metal ions. The plot of logK1(*) (human serum transferrin) versus logK1(OH) has a negative intercept consistent with unfavorable entropy effects due to lobe closure of apotransferrin on binding of metal ions. This interpretation was tested by comparison with similar correlations of the strength of metal binding to the enzymes carbonic anhydrase and carboxypeptidase with that for the low-M(r) ligand imidazole. These plots have positive intercepts consistent with the preorganized (entatic) state of these metalloenzymes (favorable entropy effects on metal binding).
Persistent Identifierhttp://hdl.handle.net/10722/167546
ISSN
2006 Impact Factor: 3.579
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorLi, Hen_US
dc.contributor.authorSadler, PJen_US
dc.contributor.authorSun, Hen_US
dc.date.accessioned2012-10-08T03:08:20Z-
dc.date.available2012-10-08T03:08:20Z-
dc.date.issued1996en_US
dc.identifier.citationEuropean Journal Of Biochemistry, 1996, v. 242 n. 2, p. 387-393en_US
dc.identifier.issn0014-2956en_US
dc.identifier.urihttp://hdl.handle.net/10722/167546-
dc.description.abstractA wide range of metal ions of natural, therapeutic, diagnostic and toxic interest are transported by serum transferrin (80 kDa). It is therefore important to understand the factors that control the strength of metal binding. We show here that even though Sc3+ has only slightly larger ionic radius than Fe3+ (0.075 nm versus 0.065 nm), it binds to the C-lobe and N-lobe sites much more weakly: logK1(*) (bicarbonate-independent binding constant) 14.6 ± 0.2, logK2(*) 13.3 ± 0.3, respectively (10 mM Hepes, 5 mM bicarbonate, 310 K). Preferential binding to the C-lobe was established by 1H-NMR spectroscopy. We show that the strength of binding of divalent and trivalent metal ions to human serum transferrin correlates with metal ion acidity [and therefore with the strength of binding to hydroxide, K1(OH)]. The correlations are of predictive value for a range of other metal ions. The plot of logK1(*) (human serum transferrin) versus logK1(OH) has a negative intercept consistent with unfavorable entropy effects due to lobe closure of apotransferrin on binding of metal ions. This interpretation was tested by comparison with similar correlations of the strength of metal binding to the enzymes carbonic anhydrase and carboxypeptidase with that for the low-M(r) ligand imidazole. These plots have positive intercepts consistent with the preorganized (entatic) state of these metalloenzymes (favorable entropy effects on metal binding).en_US
dc.languageengen_US
dc.publisherBlackwell Publishing Ltd. The Journal's web site is located at http://www.blackwellpublishing.com/journals/EJBen_US
dc.relation.ispartofEuropean Journal of Biochemistryen_US
dc.subject.meshBinding Sitesen_US
dc.subject.meshCarbonic Anhydrases - Chemistryen_US
dc.subject.meshCarboxypeptidases - Chemistryen_US
dc.subject.meshHumansen_US
dc.subject.meshIron - Metabolismen_US
dc.subject.meshKineticsen_US
dc.subject.meshMagnetic Resonance Spectroscopyen_US
dc.subject.meshMetals - Metabolismen_US
dc.subject.meshProtein Conformationen_US
dc.subject.meshScandium - Metabolismen_US
dc.subject.meshSpectrophotometry, Ultravioleten_US
dc.subject.meshTransferrin - Chemistry - Metabolismen_US
dc.titleRationalization of the strength of metal binding to human serum transferrinen_US
dc.typeArticleen_US
dc.identifier.emailSun, H:hsun@hkucc.hku.hken_US
dc.identifier.authoritySun, H=rp00777en_US
dc.description.naturelink_to_OA_fulltexten_US
dc.identifier.doi10.1111/j.1432-1033.1996.0387r.x-
dc.identifier.pmid8973657-
dc.identifier.scopuseid_2-s2.0-0029805818en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0029805818&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume242en_US
dc.identifier.issue2en_US
dc.identifier.spage387en_US
dc.identifier.epage393en_US
dc.identifier.isiWOS:A1996VW48500028-
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridLi, H=14023043100en_US
dc.identifier.scopusauthoridSadler, PJ=7103024488en_US
dc.identifier.scopusauthoridSun, H=7404827446en_US

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