Physics Commons^™

Both Nucleophile And Substrate Bind To The Catalytic Fe(Ii)-Center In The Type-Ii Methionyl Aminopeptidase From Pyrococcus Furiosus, Alicja J. Copik, Sarah Waterson, Sabina I. Swierczek, Brian Bennett, Richard C. Holz

Physics Faculty Research and Publications

Metalloproteases utilize their active site divalent metal ions to generate a nucleophilic water/hydroxide. For methionine aminopeptidases (MetAPs), the exact location of this nucleophile, as well as of the substrate, with respect to the active site metal ion is unknown. In order to address this issue, we have examined the catalytically competent Fe(II)-loaded form of PfMetAP-II ([Fe(PfMetAP-II)]) in the absence and presence of both nitric oxide (NO) and the substrate-analogue inhibitor butaneboronic acid (BuBA) by kinetic and spectroscopic (EPR, UV−vis) methods. NO binds to [Fe(PfMetAP−II)] with a K_d of 200 μM forming an {FeNO}^{7 …}