Ultraviolet Resonance Raman Spectroscopic Study on Regulatory Protein-Nucleic Acid Interactions

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The purpose of the research is threefold : construction of ultraviolet Raman apparatus, tabulation of UV Raman marker bands useful in structural study of proteins and nucleic acids, and UV resonance Raman (UVRR) spectroscopic study on cyclic AMP receptor protein (CRP) and the CRP-cAMP complex in solution.(1) UV Raman apparatusUV radiation is generated by a system consisting of a Nd : YAG laser (30 Hz), a harmonic generator (KDP or BBO), and an H_2-Raman shifter. Scattered light from a sample is dispersed (2nd order) by an f/6.8 80-cm double monochromator equipped with 600 g/mm gratings blazed at 500 nm and detected with a doubly intensified diode array of 700 pixels.(2) Table of UVRR marker bands and its applicationsUVRR spectra of peptides containing Pro, Trp, Tyr, Phe, and His, nucleosides, nucleotides, and the related compounds have been studied extensively and a list of useful structural marker bands is tabulated. Good-quality UVRR spectra of Cu, Zu-superoxide dismutase and bacteriorhodopsin have been recorded for the first time, and some pieces of structural information on the proteins are obtained on the basis of the table.(3) Structure of CRP and CRP-cAMP in dilute solutionUpon uptake of a cAMP molecule in one of the two subunits of CRP, drastic change occurs in the beta-sheet structure of the other subunit as well as the bound subunit. The adenine-ribose bond conformation is syn in the bound cAMP and the binding form is stabilized by H-bonding at N7 and C6NH_2 with side chains of the protein.