Secondary structure of the pentraxin female protein in water determined by infrared spectroscopy: effect of calcium and phosphorylcholine

Fourier transform spectroscopy was carried out to determine the secondary structure of hamster female protein (FP) in aqueous media and to evaluate calcium ion- and phosphorylcholine-induced conformational alteration. One half of the secondary structure of FP in the native form is in beta sheets with alpha helical and random structures in smaller proportion. Binding of calcium to the proposed binding sites at the regions spanning residue 93 to 109 and 150 to 168 alters FP's secondary structure. Further conformational changes is induces by phosphorylcholine. This conformational changes may explain the means by which FP's important functions are carried out.