Physical Sciences and Mathematics Commons^™

Spectroscopic And X-Ray Crystallographic Characterization Of Bestatin Bound To The Aminopeptidase From Aeromonas (Vibrio) Proteolytica, Carin C. Stamper, David L. Bienvenue, Brian Bennett, Dagmar Ringe, Gregory A. Petsko, Richard C. Holz

Physics Faculty Research and Publications

Binding of the competitive, slow-binding inhibitor bestatin ([(2S,3R)-3-amino-2-hydroxy-4-phenylbutanoy]-leucine) to the aminopeptidase from Aeromonas proteolytica (AAP) was examined by both spectroscopic and crystallographic methods. Electronic absorption spectra of the catalytically competent [Co_(AAP)], [CoCo(AAP)], and [ZnCo(AAP)] enzymes recorded in the presence of bestatin revealed that both of the divalent metal ions in AAP are involved in binding bestatin. The electron paramagnetic resonance (EPR) spectrum of the [CoCo(AAP)]−bestatin complex exhibited no observable perpendicular- or parallel-mode signal. These data indicate that the two Co^II ions in AAP are antiferromagnetically coupled yielding an S = 0 ground state and suggest …