Mass spectrometric determination of Zn2+ binding/dissociation constant for zinc finger peptides

Abstract

In the present study, we proposed a simple ESI-MS model for determining Zn2+binding (or dissociation) constants for zinc finger peptides (ZFPs) with a unique ββα fold consensus. The ionization efficiency (response) factors for this model, i.e., α and β, could be determined for ZiCo ZFP with a known Zn2+binding constant. We could determine the binding constants for other ZFPs assuming those with a ββα consensus conformation have the same α/β response ratio. In general, the ZPF dissociation constants exhibited Kd values of 10-7~10-9M, while Kd values for a negative control non-specific Zn2+peptides were high, e.g., 5.5×10-6M and 4.3×10-4M for BBA1 and melittin, respectively. © 2015, Korean Society for Mass Spectrometry. All rights reserved.