The Effect of (Non)-covalent Interactions of Small Inhibitors on the Structure of Agrobacterium sp. strain ATCC 21400 (Abg) β-glucosidase

摘要

1. Mass spectrometry results reveal that Abg dimers in solution remain intact in the gas phase. 2. In general CCS values increase with increasing charge state due to Coulomb repulsion within the ions. 3. Surprisingly, smaller collision cross sections for ions of the noncovalently bound BIC-enzyme than for ions of the covalently bound 2FG-enzyme suggest a more compact conformer for the noncovalent complex. 4. A slightly higher ΔE_(int) (～36 eV) to dissociate covalent 2FG-enzyme dimer complex compared to the apoenzyme reflects the stabilization of the free enzyme dimer by the 2FG inhibitor. 5. A direct comparison between binding inhibitors covalently and noncovalently shows noncovalent binding produces the greatest change in protein ion conformation.