| Abstract: | The vacuum-ultraviolet circular dichroism (VUCD) of chondroitin and chontroitin-6-sulfate has been measured to 160 nm for films and to 170 nm for D2O solutions. The pD-dependent dichroic behavior of these glycosaminoglycans in D2O is similar above 200 nm and is in agreement with previous studies. Near 190 nm, the CD band sign is also dependent on pD. VUCD spectra were recorded for films and solutions of poly(L -arginine). In trifluoroethanol the polypeptide is α-helical, while in D2O it exists as a random coil. The well-characterized coil–helix transition of poly(L -arginine) during complexation with chondroitin-6-sulfate was observed by VUCD, including the previously inaccessible entire π → π* band. By construction of difference spectra it was also possible to monitor the VUCD of the polysaccharide component during complexation. |
