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Protein dynamics on the microsecond (μs) time scale were investigated by temperature-jump fluorescence spectroscopy as a function of temperature in two variants of a thermophilic alcohol dehydrogenase: W87F and W87F:H43A. Both mutants exhibit a fast, temperature-independent μs decrease in fluorescence followed by a slower full recovery of the initial fluorescence. The results, which rule out an ionizing histidine as the origin of the fluorescence quenching, are discussed in the context of a Trp49-containing dimer interface that acts as a conduit for thermally activated structural change within the protein interior.

Early events in the unfolding of apomyoglobin are studied with ultraviolet resonance raman (UVRR) spectroscopy coupled to a laser-induced temperature jump. The result indicates that all of the UVRR signals show a prompt response, within the instrument resolution, which accounts for half of the total relaxation amplitude.

Different UV wavelengths for the resonant Raman excitation of hemoglobin in its two affinity states (Tand R) is explored. Changes in the T - R difference spectra as a function of excitation wavelength are reported.

Photodegradation of imidazole [ImH], 4-methylimidazole [4MeImH], and histidine during collection of UV resonance Raman [UVRR] spectra is reported. Histine degradation is an insidious problem in protein UVRR spectroscopy because of the weakness of the histidine Raman signals.

This experiment studied the radical cation and the two lowest excited singlet Rydberg states of DABCO. A framework to predict potential energy surfaces of radical cations and Rydberg states in terms of minima and Hessians is suggested.

The article discusses the use of raman spectrum and molecular orgital calculations to determine the radical cation of tetramethylbutadiene.

The isotope-edited time-resolved resonance Raman (RR) spectroscopy technique is employed to explain the CO recombination and heme structural evolution taking place in carbonmonoxy hemoglobin (Hb) protein. The various dynamical differences observed in the [alpha] and [beta] chains of Hb are also discussed.

A novel kHz repetition rate solid-state tunable NIR and deep ultraviolet Raman laser system is used for studying the dynamics of helix unfolding in Ac-GSPE[A.sub.3]K[A.sub.4]K[A.sub.4]-CO-D-Arg-CON[H.sub.2. The steeper temperature dependence for T-jump transients is attributed to greater weighting of the enthalpic stage because of the longer range sensitivity of these probes.

A truncated version of the GCN4 coiled-coil peptide was investigated by ultraviolet resonance Raman (UVRR) spectroscopy with 198 nm excitation, where amide modes are optimally enhanced. The hydrated regions of the coiled-coil peptide structure was found to melt at much lower temperature reflecting stability of the tightly bound regions from which water was excluded.

The early kinetic intermediates in the alpha-helix to beta-sheet pathway of poly(L-lysine) [poly(K)] are investigated using ultraviolet resonance Raman spectroscopy (UVRR) in combination with a nanosecond temperature jump (T-jump). The UVRR spectra shows that the thermally unfolded helix is a mixture of poly(L-proline) II (PPII) and another conformation and the intrinsic propensity for beta-strand formation could be a determinant of beta-sheet induction time.

Conformational transition to [beta]-sheet structure in cytochrome c (cyt c) is seen through Resonance Raman (RR) spectroscopy. The cardiolipin binding to cyt c induces a conformational switch to the [beta]-sheet structure resulting in heme exposure and cardiolipin peroxidation and apoptosis and this could be due to H-bonding of the anionic cardiolipin head group.