STUDYING TRPZIPS USING RESONANCE RAMAN SPECTROSCOPY

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Folding dynamics of beta-hairpins has been a prominent area of studies in the Gai group. We have investigated the structural stability and folding kinetics of a series of beta-hairpins, namely: tryptophan zippers, by static Infrared spectroscopy, Circular Dichroism and the Infrared temperature jump method. To further extend our understanding of this system, we plan to collaborate with Dr. Spiro¿s lab and use Resonance Raman Spectroscopy in a time resolved mode to study the dynamics of motion of tryptophan zippers (Trpzips). Tryptophan is an aromatic residue and is believed to be involved in H- bonding interactions, and thus can be used as probes of motion at various sites in the protein. Therefore, Trpzips are an ideal system for Resonance Raman Spectroscopy because we can use wavelength-selective laser excitation to monitor Resonance Raman spectra of the tryptophan sidechains and thus monitor the motion of Trpzips. We plan look at investigate Trptophan residues in the Trpzips at 229 nm wavelength and amide bands excited below 200 nm wavelength. The sequence of the peptide used in the current study is as following: Trpzip2: SWTWENGKWTWK. For preliminary studies, we would like to do one set of static measurement and 1 to 5 sets of T-jump measurements so as to check the activation energy. If we obtain favorable results we will extend the study further.