Assignment of major Raman bands of ASBVds. Raman spectra of ASBVd(-) ((a), blue curve) and ASBVd(+) ((b), red curve) are obtained in aqueous cacodylate buffer, in the absence of Mg2+. Both spectra were normalized using the Raman band at 1100 cm-1 taken as an internal intensity standard, and the contributions from the cacodylate buffer and quartz cell were subtracted. The black curve (c) is the difference Raman spectrum obtained by (1:1) subtraction of the spectrum (a) from spectrum (b). The difference spectrum (c) was multiplied by a factor of 3 to visually enhance the resulting spectral changes.