TY - JOUR
T1 - Surface plasmon resonance measurement of pH-induced responses of immobilized biomolecules: conformational change or electrostatic interaction effects?
AU - Paynter, Sally
AU - Russell, David A.
PY - 2002
Y1 - 2002
N2 - Recently, the observation of pH-induced conformational changes of biomolecules supported on carboxymethyldextran (CMD)-coated surfaces measured using surface plasmon resonance (SPR) has been reported. However, it is apparent that the evidence reported in the literature is ambiguous. The research presented in this paper describes investigations to study the changing SPR signal of immobilized biomolecules as a function of varying pH, to provide a detailed understanding of the origin of the pH-induced changes in the SPR profile. SPR measurements were performed with cytochrome c, concanavalin A, and poly-Image -lysine, biomolecules that exhibit diverse conformational responses to changing pH, covalently immobilized onto CMD-coated supports. These SPR measurements were supported by circular dichroism (CD) solution studies. The SPR profiles recorded were not consistent with the conformational transitions of the biomolecules as observed using CD. An alternative explanation for the observed shifts in SPR is proposed, which explains the SPR profiles in terms of electrostatic interaction effects between the immobilized biomolecules and the carboxymethyldextran matrix.
AB - Recently, the observation of pH-induced conformational changes of biomolecules supported on carboxymethyldextran (CMD)-coated surfaces measured using surface plasmon resonance (SPR) has been reported. However, it is apparent that the evidence reported in the literature is ambiguous. The research presented in this paper describes investigations to study the changing SPR signal of immobilized biomolecules as a function of varying pH, to provide a detailed understanding of the origin of the pH-induced changes in the SPR profile. SPR measurements were performed with cytochrome c, concanavalin A, and poly-Image -lysine, biomolecules that exhibit diverse conformational responses to changing pH, covalently immobilized onto CMD-coated supports. These SPR measurements were supported by circular dichroism (CD) solution studies. The SPR profiles recorded were not consistent with the conformational transitions of the biomolecules as observed using CD. An alternative explanation for the observed shifts in SPR is proposed, which explains the SPR profiles in terms of electrostatic interaction effects between the immobilized biomolecules and the carboxymethyldextran matrix.
U2 - 10.1016/S0003-2697(02)00255-5
DO - 10.1016/S0003-2697(02)00255-5
M3 - Article
SN - 1096-0309
VL - 309
SP - 85
EP - 95
JO - Analytical Biochemistry
JF - Analytical Biochemistry
IS - 1
ER -