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Binding of oxovanadium(IV) to dipeptides containing histidine and cysteine residues

Garribba, Eugenio and Lodyga-Chruscinska, Elzbieta and Micera, Giovanni and Panzanelli, Angelo and Sanna, Daniele (2005) Binding of oxovanadium(IV) to dipeptides containing histidine and cysteine residues. European Journal of Inorganic Chemistry, Vol. 2005 (7), p. 1369-1382. eISSN 1099-0682. Article.

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DOI: 10.1002/ejic.200400576

Abstract

The complexation of the oxovanadium(IV) ion with five dipeptides containing L-histidine or L-cysteine (GlyHis, HisHis, HisGly, CysGly, GlyCys) was studied. L-histidinamide (HisNH2) was assumed as a model system for dipeptides with L-histidine in the N-terminal position. The study was performed in aqueous solution through the combined application of potentiometric and spectroscopic (electronic absorption and EPR) techniques. The results indicate that simple dipeptides lacking a strong anchoring group can form mono- and bischelated complexes with the VIVO ion if a suitable donor is present in the chain. The ligands behave like amino acids in the acidic and neutral pH range, inhibit the precipitation of hydroxides and suppress the formation of hydrolytic species if at least a fivefold molar excess of ligand is used. In alkaline media all the ligands, except CysGly, promote the deprotonation and N-coordination of the amide group. CysGly forms a bischelated complex with a [2 (NH2, S-)] donor set. The contribution of the deprotonated amide group to the 51V hyperfine coupling constant, Az, as a function of the total equatorial charge of oxovanadium(IV) ion, is discussed. The results have general validity and are useful to predict the geometry and donor set of complexes involving the bonding of the VIVO ion to the deprotonated amide group.

Item Type:Article
ID Code:2273
Status:Published
Refereed:Yes
Uncontrolled Keywords:Vanadium, peptides, bioinorganic chemistry, EPR spectroscopy, coordination modes, bond theory
Subjects:Area 03 - Scienze chimiche > CHIM/03 Chimica generale e inorganica
Area 03 - Scienze chimiche > CHIM/01 Chimica analitica
Divisions:001 Università di Sassari > 01 Dipartimenti > Chimica
002 Altri enti e centri di ricerca del Nord Sardegna > CNR-Consiglio Nazionale delle Ricerche > Istituto di chimica biomolecolare, Sassari
Publisher:Wiley
eISSN:1099-0682
Deposited On:18 Aug 2009 10:07

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