Glycoconjugate biochemistry : structure-function relationship

• Main Author: Nasir-ud-Din
• Published: University of Edinburgh 1996
• Subjects: 572.56
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.659886

In this thesis studies on the following glycoconjugates are presented: bacterial, <I>Micrococcus lysodeikticus, </I>cell wall, simian cervical mucin, human pulmonary mucin, bovine gallbladder mucin, sperm surface glycoproteins and glycoconjugates of malarial parasite, <I>Plasmodium falciparum. </I>The information obtained on the structure of these complex carbohydrates utilising chemical, enzymatic, immunological and physical methods provided insight into the understanding, in particular, of structure-function relationship, degradation and biosynthesis of these macromolecules. Studies on model compounds and analytical methods, all of which are vitally important tools in the study of glycoconjugates, are also described. The carbohydrate prosthetic group of <I>Micrococcus lysodeikticus </I>cell wall was shown to consist of a glycan moiety linked to the protein and an antigenic polysaccharide attached to the glycan moiety of the peptidoglycan through a phosphodiester group. A variety of model compounds were synthesised to establish the structure of the carbohydrate moiety as well as to study the kinetics if the acid hydrolysis of the phosphodiester group linked to muramic acid and to the reducing terminus of glucose. The study was performed on <I>Micrococcus lysodeikticus </I>cell wall polymer resistant to lysozyme, elaborating the structural requirement for stability to the enzyme. Furthermore, a water soluble polymer from the <I>Micrococcus lysodeikticus </I>cell wall was isolated and characterised, a novel observation. The study on this polymer suggested the possible deficiencies in the biosynthesis or possible autolysis of the cell wall polymer. A large number of model compounds were chemically synthesised to identify the structural features of the cell wall peptidoglycans and those of the antigenic polysaccharide. In addition, several compounds were chemically synthesised to obtain the model compounds necessary to conduct kinetic studies to define the type of linkage, i.e. differentiate between the monophosphate or pyrophosphate, between the cell wall polysaccharide and peptidoglycan, more precisely the linkage between muramic acid 6-phosphate of the peptidoglycan and the reducing terminal residue, glucose, of the polysaccharide.