NANOSECOND CIRCULAR-DICHROISM SPECTRAL MEASUREMENTS - EXTENSION TO THE FAR-ULTRAVIOLET REGION

The first measurements of time-resolved circular dichroism in the far-UV spectral region (far-UV-TRCD) with time resolution on the order of 10(-7) s are presented. The capability of making such measurements is demonstrated with ground- and excited-state CD spectra of (DELTA)-Ru(bpy)3(2+) between 190 and 290 nm as well as with CD spectra of a short peptide measured at different pHs. The properties of the far-UV-TRCD technique are discussed in detail, and comparisons between the static CD spectra obtained by this technique and those obtained by a conventional CD spectrometer are presented. Possible improvements to the current technique and application of the technique to resolve biophysical problems such as the kinetics of peptide helix-coil transition are also discussed.