Fourier-Transform Infrared Spectroscopic Investigation of the Secondary Structure of P₂ Protein in Deuterium Oxide Solution

Abstract

Fourier transform infrared ( F.t.i.r .) spectroscopy has been used to investigate the secondary structure of bovine P₂ protein in deuterium oxide (D₂O) solution. The amide 1 region of the spectrum was analysed quantitatively by means of resolution enhancement and band-fitting procedures. The protein was found to consist mainly of β-structure (61%), with a small amount of α-helix (11%). A reason for the existence of an unusually intense low-frequency band assigned to β-structure is discussed. The F.t.i.r . results are compared with those from an X-ray crystallographic study and from circular dichroism and explanations are offered for discrepancies between the results from the different methods.