Ligand Rebinding: Self-consistent Mean-field Theory and Numerical Simulations Applied to SPR Studies

摘要: Rebinding of dissociated ligands from cell surface proteins can confound quantitative measurements dissociation rates important for characterizing the affinity binding interactions. This be true also in vitro techniques such as plasmon resonance (SPR). We present experimental results using SPR interaction insulin-like growth factor-I (IGF-I) with one its proteins, IGF protein-3 (IGFBP-3), and show that rebinding, even addition soluble heparin phase, does not exhibit expected exponential decay characteristic a 1:1 reaction. thus consider effect (multiple) rebinding events and, within self-consistent mean-field approximation, we derive complete mathematical form fraction bound ligand function time. that, except very low coverage/association rate, this is non-exponential at all times, indicating multiple strongly influence early times. compare numerical simulations find good agreement, although deviations are measurable certain cases. Our analysis IGF-I-IGFBP-3 data indicates prominent system theoretical predictions fit well. provide means analyzing biosensor where problematic methodology to do so presented.