Scientists from Umeå University in Sweden have come up with a straightforward way of measuring distances within protein molecules using fluorescence spectroscopy.
Scientists from Ume? University in Sweden have come up with a straightforward way of measuring distances within protein molecules using fluorescence spectroscopy. The technique, dubbed ’partial donor-donor energy migration’ (PDDEM), involves covalently incorporating chemically identical fluorophores into a protein and making them photophysically different by adding a quenching agent. The distance between the two fluorophores can then be worked out by measuring the rate of fluorescence relaxation.
Lennart Johansson and colleagues demonstrated the method by successfully measuring the distance between two cysteine residues in the protein ’PAI-2’. As PAI-2 is a widely studied protein, Johansson could confirm that the new method is accurate. ’A comparison between PDDEM and [other methods] shows the distances in PAI-2 are very similar.
’In addition the PDDEM method is a more straightforward experimental process’, he explained. Measuring the distance between two specific residues, using methods like PDDEM, can tell researchers how a protein folds; something which the medical community is increasingly interested in. Misfolded proteins, or ’prions’, could be the chief cause of conditions like BSE, CJD and Alzheimer’s disease.
M Isaksson et al, Phys. Chem. Chem.Phys., 2004 (DOI: 10.1039/ <MAN>b403264k</MAN>)