The Raman and FTIR spectra of a murine IgG2a monoclonal antibody molecule i
n anhydrous state and in aqueous solutions of H2O and D2O are reported. The
secondary structural characteristics have been investigated and have been
established from absorption measurements in the amide I, I' and II, II' fre
quency range. In an anhydrous state, in accordance with previous studies on
immunoglobulins, the secondary structures is predominantly of the beta-she
et type. Data obtained in different polar media (KBr, H2O, D2O) reveal that
IgG2a is a highly flexible protein. In pure H2O and D2O a rapid solvation
of free peptide units occurs.