D. Groche et al., ISOLATION AND CRYSTALLIZATION OF FUNCTIONALLY COMPETENT ESCHERICHIA-COLI PEPTIDE DEFORMYLASE FORMS CONTAINING EITHER IRON OR NICKEL IN THE ACTIVE-SITE, Biochemical and biophysical research communications, 246(2), 1998, pp. 342-346
Three metallo forms of peptide deformylase (PDF, EC 3.5.1.31) of Esche
richia colt were prepared and crystallized (space group C2, diffractio
n limit 1.9 Angstrom) for initiating the X-ray structure determination
of the metal center in correlation with the catalytic function ality
of this enzyme. The native Fe2+ containing enzyme species was directly
isolated from overproducing bacteria by using catalase as a buffer ad
ditive, which stabilizes the catalytic activity against oxidative dest
ruction. The Ni2+ containing form, which is oxygen-insensitive, was ob
tained by metal exchange with free Ni+2 and found to be catalytically
equally effective (k(cat)/K-M = 10(5) M-1 s(-1) for N-formyl-Met-Ala).
The Zn2+ form, prepared from the apoenzyme or by displacement of boun
d Ni2+ by free Zn2+, proved virtually inactive. (C) 1998 Academic Pres
s.