Prof Parker says: "We have found a way to use the inherent chirality of light to examine the interaction at the molecular level between a probe (the optical probe, itself of one handedness) and serum albumin (also of one handedness: hence akin to a hand/glove interaction) - the most abundant protein in blood."
Based on a chiral lanthanide complex, the probe emits circularly polarised light that inverts sign on protein binding; monitoring the emitted light allows researchers to follow the interaction between the complex and the protein.
Observing this luminescence is a way of studying the chirality of the system, explains Prof Parker: "The optical signal we observed carries information in its circular polarisation. It's a tricky process. You have to get the light in and out of the cells but crucially, in terms of biology, it can be done using microscopes in the laboratory so it's non-invasive."
The researchers found that only one enantiomer of certain europium and terbium complexes bound selectively to a drug binding site of the protein serum albumin, and that the luminescence changed dramatically. Prof Parker says: "This is the first example of chiral inversion using an emissive probe in this way."
The researchers have been seeking to develop responsive optical probes for a while and were delighted when they finally cracked it.
Prof Parker said: "We were genuinely surprised. The binding energy and kinetics have to be just right - we've been lucky. Potentially this technology could be used to track protein association in living cells in real time."
|Contact: Alex Thomas|