Raman spectroscopic study of the structure of antibodies

The Raman spectra of human IgG, IgM, and rabbit IgG in lyophilized form and solution are reported. The spectral results indicate that the predominant structure in these immunoglobulin proteins is the antiparallel β‐sheet. The Raman spectra have also been obtained of rabbit anti‐ovalbumin, and this antibody molecule precipitated with its respective antigen. The spectra reflect a conformational change on binding of antibody with antigen. The conformational change occurs in the direction of disordering.