Quantitative static and time-resolved singlet energy transfer measurements as well as fluorescence anisotropy measurements are reported for the specific complex formed between the luminescent derivative of CcP, (MgCcP), and Cc from yeast and higher eukaryotes. Significant differences were found in the ionic strength dependent binding of yeast and horse Cc, suggesting a different balance of interactions for these species within the binding domain. Small differences are also apparent in the bound MgCcP/Cc singlet-state energy transfer dynamics as monitored by fluorescence quenching. Dynamic measurements show energy transfer is more efficient for yeast Cc than for horse Cc, also consistent with some differences in the docking geometry with CcP between horse Cc and yeast Cc. Overall results suggest some plasticity in the binding of Cc and CcP, with a distribution of complex conformations that depends on species specific interactions. Evidence for a dynamic redistribution among these conformations includes the observation of energy transfer kinetics that appear quite complex at 77 K, but are significantly simplified by dynamic averaging at 300 K.
ASJC Scopus subject areas
- Colloid and Surface Chemistry