Copper(II) complexes of terminally protected pentapeptides containing three histidyl residues in alternating positions, Ac-His-Xaa-His-Yaa-His-NH2
Φόρτωση...
Ημερομηνία
Συγγραφείς
Kallay, C.
Varnagy, K.
Malandrinos, G.
Hadjiliadis, N.
Sanna, D.
Sovago, I.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
Royal Society of Chemistry
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Dalton Transactions
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
Copper(II) complexes of the pentapeptides Ac-HisAlaHisValHis-NH2, Ac-HisValHisAlaHis-NH2, Ac-HisProHisAlaHis-NH2, Ac-HisAlaHisProHis-NH2, Ac-HisGlyHisValHis-NH2 and Ac-HisValHisGlyHis-NH2 have been studied by potentiometric, UV-Vis, CD and EPR spectroscopic methods. It has been found that the pentapeptides are efficient ligands for the complexation with copper( II) and exhibit an outstanding versatility in the co-ordination geometry of complexes. The presence of three histidyl residues provides a high possibility for the formation of macrochelates via the exclusive binding of imidazole-N donor atoms. The macrochelation suppresses, but cannot preclude the deprotonation and metal ion co-ordination of amide functions and the species [CuH-2L] and [Cu2H-4L] predominate at physiological pH in equimolar solutions and in the presence of excess metal ions, respectively. It is also clear from the data that both C-terminal and internal histidyl residues can work as the anchoring sites for metal binding and subsequent amide deprotonation resulting in the formation of co-ordination isomers and dinuclear species in equimolar solutions and in the presence of excess metal ions, respectively. In more alkaline solutions ( pH similar to 10) a third amide function can be deprotonated and co-ordinated in the species [CuH-3L](-) with (N-, N-, N-, N-im) co-ordination. The dinuclear species [Cu2H-5L](-) and [Cu2H-6L](2-) containing hydroxide ions and/or imidazolato bridges are formed at high pH in the presence of excess of metal ions. The insertion of one proline into the sequence preceding histidyl residues hinders the deprotonation of amide functions at that site and the formation of only mononuclear complexes was observed with these peptides.
Περιγραφή
Λέξεις-κλειδιά
transition-metal-complexes, imidazole nitrogen donors, amyloid precursor protein, prion protein, ion coordination, model peptides, binding site, cu2+ ions, stability, fragments
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000240935300003
http://pubs.rsc.org/en/content/articlepdf/2006/dt/b608190h
http://pubs.rsc.org/en/content/articlepdf/2006/dt/b608190h
Γλώσσα
en
Εκδίδον τμήμα/τομέας
Όνομα επιβλέποντος
Εξεταστική επιτροπή
Γενική Περιγραφή / Σχόλια
Ίδρυμα και Σχολή/Τμήμα του υποβάλλοντος
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας