O-acetylation Analysis Of N-glycans In Natural Polymers And Its Application For The Toxicity Evaluation Of Perovskite Photovoltaic Materials

Proteins are natural polymer compounds and an integral part of life activities.N-linked glycosylation enriches the structure and function of proteins as a wide-ranging and important post-translational modification of proteins.As a result,the proteins modified with N-glycans are involved in the life activities of various stages of the organism.The diverse biological functions make N-glycans research has important clinical medical value and biological significance.As an important biological population in the wetland ecosystem,the carp has a wide range of interactions with water bodies and other organisms.The study of the structure and function of the biological macromolecules in carp is useful in characteristization of carp's life activities and risk assessment of water environment.However,the studies of biomacromolecules has been very limited for carp,especially on glycosomics.Based on MALDI-TOF-MS,we identified the serum N-glycans of toxic exposed carp,compared and discussed the differences in the abundance of serum N-glycans with exposure time.It was found that perovskite material FAPbBr3 had impact on N-glycans.The LCMS/MS analysis of methylated N-glycans from carp serum indicated the presence of abundant O-acetylation.The heterogeneous distribution of O-acetylation at sialic acid and their corresponding positions were obtained.LC-Orbitrap-MS/MS experiment was then performed for the N-glycans after dual modification,e.g.animination and methylamidation.The results offered the information on O-acetylation,including number of acetyl groups and their corresponding positions.Furthermore,the structural isomers with the distribution of Oacetyl groups was derived from the fragmentation pattern of intact glycan.The relative quantitation of N-glycans in two samples was achieved by combining aniline and deuterated aniline for dual modification,which resulted a mass difference of 5 Da due to the isotopic aniline labeling.The work presented in this thesis enriches the biological information of glycosylation in carp serum.It is anticipated that the established method has a wide application potential in the research of sialic acid modification and discovery of glycoprotein-based biomarkers.