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Investigation of the active site of Escherichia coli Cu,Zn superoxide dismutase reveals the absence of the copper‐coordinated water molecule. Is the water molecule really necessary for the enzymatic mechanism?
Author(s) -
Sette Marco,
Bozzi Manuela,
Battistoni Andrea,
Fasano Mauro,
Paci Maurizio,
Rotilio Giuseppe
Publication year - 2000
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(00)02074-3
Subject(s) - superoxide dismutase , copper , chemistry , escherichia coli , enzyme , molecule , active site , biochemistry , organic chemistry , gene
The active site of the Cu,Zn superoxide dismutase from Escherichia coli in the oxidized Cu(II) state has been studied by nuclear magnetic relaxation dispersion (NMRD), optical and nuclear magnetic resonance spectroscopy. The orientation of some metal ligands is different with respect to all the other Cu,Zn superoxide dismutases. Moreover, NMRD measurements demonstrate the lack of a copper‐coordinated water molecule. In spite of these differences the enzymatic activity is still high. Azide also binds copper with normal affinity and induces modifications in the active site comparable to those previously observed in the eukaryotic enzymes. Our results suggest that, in this enzyme, the copper‐coordinated water molecule appears not necessary for the enzymatic reaction. A role for the copper‐coordinated water molecule is discussed in the light of recent crystallographic studies.