FTIR investigation of the effects of ultra-strong static magnetic field on the secondary structures of protein in bacteria

Secondary structures of protein in Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) exposed to the ultra-strong static magnetic field (SMF) were investigated by Fourier transformation infrared spectroscopy (FTIR). Difference index D value of amide I (1600–1700 cm⁻¹) showed that the ultra-strong magnetic field had little impact on S. aureus, but had strong impact on E. coli. The results indicated that 3.46–9.92% of the disorder coils in the secondary structures of protein in E. coli were turned into α-helices under SMF while applying deconvolution and curve fitting to amide I. At the same time, intermolecular β-sheets transforming into intramolecular ones suggested that cohesion among protein molecules had been destroyed and intramolecular hydrogen bonds strengthened. All the differences among the compositions of protein’s secondary structures in E. coli were mostly due to the varying degrees of various proteins affected by the magnetic field. The results may provide new insights into the structural changes of proteins induced by the SMF.