Document Detail

A search for hyperglycosylation signals in yeast glycoproteins.
MedLine Citation:
PMID:  15280361     Owner:  NLM     Status:  MEDLINE    
N-oligosaccharides of Saccharomyces cerevisiae glycoproteins are classified as core and mannan types. The former contain 13-14 mannoses whereas mannan-type structures consist of an inner core extended with an outer chain of up to 200-300 mannoses, a process known as hyperglycosylation. The selection of substrates for hyperglycosylation poses a theoretical and practical question. To identify hyperglycosylation determinants, we have analyzed the influence of the second amino acid (Xaa) of the sequon in this process using the major exoglucanase as a model. Our results indicate that negatively charged amino acids inhibit hyperglycosylation, whereas positively charged counterparts promote it. On the basis of the tridimensional structure of Exg1, we propose that Xaa influences the orientation of the inner core making it accessible to mannan polymerase I in the appropriate position for the addition of alpha-1,6-mannoses. The presence of Glu in the Xaa of the second sequon of the native exoglucanase suggests that negative selection may drive evolution of these sites. However, a comparison of invertases secreted by S. cerevisiae and Pichia anomala suggests that hyperglycosylation signals are also subjected to positive selection.
Raúl Conde; Rosario Cueva; Guadalupe Pablo; Julio Polaina; Germán Larriba
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2004-07-26
Journal Detail:
Title:  The Journal of biological chemistry     Volume:  279     ISSN:  0021-9258     ISO Abbreviation:  J. Biol. Chem.     Publication Date:  2004 Oct 
Date Detail:
Created Date:  2004-10-11     Completed Date:  2004-12-14     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2985121R     Medline TA:  J Biol Chem     Country:  United States    
Other Details:
Languages:  eng     Pagination:  43789-98     Citation Subset:  IM    
Universidad de Extremadura, Departamento de Microbiología, F de Ciencias, 06071 Badajoz, Spain.
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MeSH Terms
Amino Acid Sequence
Fungal Proteins / chemistry
Glycoproteins / chemistry*
Models, Molecular
Oligosaccharides / analysis*,  chemistry
Protein Conformation
Saccharomyces cerevisiae / chemistry*
Saccharomyces cerevisiae Proteins / chemistry*
Reg. No./Substance:
0/Fungal Proteins; 0/Glycoproteins; 0/Oligosaccharides; 0/Saccharomyces cerevisiae Proteins

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