[1] Yale Univ, Dept Mol Biophys & Biochem, New Haven, CT 06520 USA
[2] Yale Univ, Dept Chem, New Haven, CT 06520 USA
[3] Univ Cambridge, Chem Lab, Cambridge CB2 1EW, England
[4] Univ Sussex, Dept Chem, Chem Biol Unit, Brighton BN1 9QG, E Sussex, England
[5] MRC, Canc Cell Unit, Hutchison MRC Res Ctr, Cambridge CB2 2XZ, England
[6] Yale Univ, Dept Phys, New Haven, CT 06520 USA
[7] Yale Univ, Dept Appl Phys, New Haven, CT 06520 USA