Raman spectroscopic study of Leptospiral Glycolipoprotein

The Raman scattering spectra of two different samples of Leptospiral Glycoipoprotein (GLP--1 and GLP--2) which have different toxic effects have been obtained and investigated. Leptospirosis is one of the most harmful zoonosis. It is a serious public health issue in some area of Sichuan province. The two samples offer different structural informations of GLP molecules,it would be important to find the difference in contents,structures and the amino acid side--chains environment of the molecules between the two samples of GLP for understanding the different toxic effects. The intense Am I at 1651cm(-1) and weak Am III at 1283cm(-1) show that GLP--1 has a predominanty alpha-helix secondary structure. The intense Am I at 1674cm(-1) and intense Am III at 1246cm(-1) show that the conformation of GLP--2 has a high content of beta--sheet and a low content of random--coil secondary structure. Strong Raman scattering occurs in the range 920 similar to 980 cm(-1),belong to the C--COO- vibration and the stretching of the peptide backbone. The molecules of GLP--1 has trans--gauche--trans configuration of the C-S-S-C-C linkage and the molecules of GLP--2 has trans--gauche--gauche configuration of the C-C-S-S-C-C linkage. The intensity ratio of the two tyrosine lines at 830cm(-1) and 850cm(-1) is 1.1 (GLP--1) and 1.23 (GLP--2),indicate their tyrosine reduses environment respectively. Other side--chain environment in the tyro samples were discussed.