Identification and Quantification of Protein Glycosylation

Glycosylation is one of the most abundant posttranslation modifications of proteins, and accumulating evidence indicate that the vast majority of proteins in eukaryotes are glycosylated. Glycosylation plays a role in protein folding, interaction, stability, and mobility, as well as in signal transduction. Thus, by regulating protein activity, glycosylation is involved in the normal functioning of the cell and in the development of diseases. Indeed, in the past few decades there has been a growing realization of the importance of protein glycosylation, as aberrant glycosylation has been implicated in metabolic, neurodegenerative, and neoplastic diseases. Thus, the identification and quantification of protein-borne oligosaccharides have become increasingly important both in the basic sciences of biochemistry and glycobiology and in the applicative sciences, particularly biomedicine and biotechnology. Here, we review the state-of-the-art methodologies for the identification and quantification of oligosaccharides, specifically N- and O-glycosylated proteins.

Cultivation System Using Glass Beads Immersed in Liquid Medium Facilitates Studies of Streptomyces Differentiation

ABSTRACT A two-phase cultivation system was developed which will enable studies of streptomycete differentiation by molecular biological and global techniques such as transcriptomics and proteomics. The system is based on a solid phase formed by glass beads corresponding to particles in soil, clay, or sand natural habitats of streptomycetes. The beads are immersed in a liquid medium that allows easy modification or replacement of nutrients and growth factors as well as radioactive labeling of proteins. Scanning electron microscopy was used to analyze morphological differentiation of streptomycetes on glass beads and two-dimensional protein electrophoresis to demonstrate the potential of the system for analyses of protein synthesis profiles during the developmental program. This system facilitates studies of differentiation including expression and posttranslation modifications of streptomycetes proteins, secondary metabolite biosynthesis, and morphological development.