Department of Biochemistry
Iowa City, IA 52242-1109 USA
fax: (319) 335-9570
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Rex Montgomery, PhD
Carver College of Medicine
University of Iowa, 4-403 BSB
Biochemistry/Univ. of Iowa
Iowa City, IA 52242
Fax: (319) 335-9570
It is becoming increasingly recognized that the carbohydrate groups in glycoproteins and glycolipids can play important roles in biological functions, such as cellular transport processes, communication and defense mechanisms. Frequently the carbohydrate groups are small components of the molecule and their structures are polydisperse and microheterogeneous. The isolation of these molecules from biological systems in pure form is difficult, limited in many instances to gel electrophoresis or microchromatographic techniques. Commensurate with these technologies, the structural elucidation of the carbohydrate groups, preparative to structure-function studies, must be possible at picomole levels, such as would be obtainable from gel electrophoresis bands.
The degrees of structural detail would involve an evaluation of molecular purity, compositional analysis, mapping of the oligosaccharide microheterogeneity, linkage analyses and exoglycosidase-assisted sequencing and conformational analysis. Such studies combine the technologies of chromatography, spectrometry (such as UV/IR, NMR, GC/MS, FABS), mass spectrometry, microanalysis, microchemistry, and enzymology.
Examples of the application of these structure-function analyses include:
Extracellular microbial polysaccharides. The polysaccharides of species of the phytopathogen Erwinia chrysanthemi have been shown to be polyrhamnoglucuronoglucomannans with the exception so far of one case that is a polyfucoglucuronoglucogalactan. The pathogenicity of each of these species is different and may reflect in part the extracellular polysaccharide.
Peroxidases. The peroxidases of horseradish and soybean are glycoproteins, the several carbohydrate groups of which are distributed along the polypeptide chain. Studies are in progress to determine the relationship of these glycan groups to the enzymatic activity.
Lipopolysaccharides. Each of the several types of Legionella pneumophila has a specific membrane-bound antigen, the characterizations of which are important to the diagnosis of Legionnaires' disease. The structural aspects of each serotype antigen are being elucidated. Upon gel electrophoresis the lipopolysaccharides form a "ladder" of components and the relationship of each "rung" of the ladder to another rung is unknown. The microanalytical techniques are being applied to the study of lipopolysaccharides.
Microanalyses. The microanalytical techniques have been applied to the analysis of inositol phosphates in corn, the lipophilic compounds in fermentation byproducts and the process of corn steeping.
Yang, B.Y., and Montgomery, R. (2007) Alkaline degradation of invert sugar from molasses. Bioresour. Technol. 98:3084-3089.
Gray, J.S.S., and Montgomery, R. (2006) Asymmetric glycosylation of soybean seed coat peroxidase. Carbohydr. Res. 341:198-209.
Yang, B.Y., and Montgomery, R. (2006) Acylation of starch using trifluoroacetic anhydride promoter. Starch/St?rke 58:520-526.
Yang, B.Y. and Montgomery, R. (2005) Oxidation of lactose with bromine. Carbohyr. Res. 340:2698-2705.
Ding, Q., Yang, B.Y. and Montgomery, R. (2004) Structure and hydrodynamic properties of the extracellular polysaccharide from a mutant strain (RA3W) of Erwinia chrysanthemi RA3. Carbohydr. Res. 339(11):2049-2053.
Montgomery, R. (2004) Development of biobased products. Bioresource Tech. 91:1-29. Yang, B.Y., LaBelle, M., Ding, Q., and Montgomery, R. (2003) Physiochemical studies of extracellular polysaccharides of Erwinia chrysanthemi spp. Carbohydr. Polymers 51:336-346.
Yang, B.Y., Ding, Q., Montgomery, R. (2003) Hydrodynamic properties of oxidized extracellular polysaccharides from Erwinia chrysanthemi spp. Carbohydrate Res. 338:2763-2771.
Yang, B.Y., Montgomery, R. (2003) De-icers derived from corn steep water. Bioresource Tech. 90:265-273.
Gray, J.S.S. and Montgomery, R. (2003) Purification and characterization of a peroxidase from corn steep water. J. Agric. Food Chem. 51:1592-1601.
Ding, Q., LaBelle, M., Yang, B.Y., and Montgomery, R. (2003) Physiochemical studies of extracellular polysaccharides of Erwinia chrysanthemi spp. Carbohydr. Polymers 51:333-346.
Yang, B.Y., Ding, Q., Montgomery, R. (2002) Extracellular polysaccharides of Erwinia futululu, a bacterium associated with a fungal canker disease of Eucalyptus spp. Carbohydr. Res. 337:2469-2480.
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