Complexation of Cu2+ by HETPP and the pentapeptide Asp-Asp-Asn-Lys-Ile: A structural model of the active site of thiamin-dependent enzymes in solution
Φόρτωση...
Ημερομηνία
Συγγραφείς
Malandrinos, G.
Louloudi, M.
Deligiannakis, Y.
Hadjiliadis, N.
Τίτλος Εφημερίδας
Περιοδικό ISSN
Τίτλος τόμου
Εκδότης
American Chemical Society
Περίληψη
Τύπος
Είδος δημοσίευσης σε συνέδριο
Είδος περιοδικού
peer reviewed
Είδος εκπαιδευτικού υλικού
Όνομα συνεδρίου
Όνομα περιοδικού
Inorg Chem
Όνομα βιβλίου
Σειρά βιβλίου
Έκδοση βιβλίου
Συμπληρωματικός/δευτερεύων τίτλος
Περιγραφή
To obtain structural information on the active site of thiamin-dependent enzymes in solution, we have studied the interactions of Cu2+ ions with 2-(alpha -hydroxyethyl)thiamin pyrophosphate (HETPP), the pentapeptide Asp-Asp-Asn-Lys-IIe surrounding the thiamin pyrophosphate moiety in the transketolase enzyme, and the tertiary CU(2+)pentapeptide-HETPP system in aqueous solutions at various pH values. In the binary Cu2+-pentapeptide system around physiological pH, the bonding sites were the terminal NH2 group, the aspartate beta -carboxylates, and a deprotonated peptide nitrogen, while, in the Cu2+-HETPP system at the same pH, the Cu(II) was coordinated to the pyrophosphate group and to the pyrimidine N(1') atom. It is found that, in the tertiary system at physiological pH, the, peptide bone offers three coordination sites to the metal ion, and the coordination sphere is completed by two additional phosphate oxygens and the nitrogen N(1') of the thiamin coenzyme. The stability constants in the, tertiary system are higher than those in the simpler CU2+-HETPP and CU2+-peptide systems. The present data show that the coenzyme adopts the so-called S conformation in solution. The importance of our findings concerning the N(1') coordination and the S conformation in the tertiary system is discussed in conjunction with the role of HETPP as an intermediate of thiamin catalysis.
Περιγραφή
Λέξεις-κλειδιά
crystal-structure, pyruvate decarboxylase, metal-complexes, copper(ii) complexes, angstrom resolution, diphosphate, pyrophosphate, catalysis, chloride, residues
Θεματική κατηγορία
Παραπομπή
Σύνδεσμος
<Go to ISI>://000170642600015
http://pubs.acs.org/doi/pdfplus/10.1021/ic001465t
http://pubs.acs.org/doi/pdfplus/10.1021/ic001465t
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