ISSN:
0749-503X
Keywords:
dolichol-PP-GlcNAc2
;
translocation
;
endoplasmic reticulum
;
alg1
;
exoglucanase
;
S. cerevisiae
;
Life and Medical Sciences
;
Genetics
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
Notes:
Transfer of truncated oligosaccharides to yeast exoglucanase (Exg) in Saccharomyces cerevisiae alg1 has been investigated. When incubated at the non-permissive temperature, alg1 cells secreted into the culture medium, in addition to the exoglucanase glycoforms secreted by wild type, underglycosylated forms as well as material with ionic properties of the non-glycosylated enzyme. As expected, none of the latter had affinity towards concanavalin A, but part of it bound to wheat germ agglutinin (WGA), suggesting that it contained, in addition to non-glycosylated Exg, glycoforms carrying non-reducing terminal GlcNAc. Only the WGA-bound material could be labelled with galactosyltransferase; furthermore, the label could be released by treatment with peptide-N4-N-acetyl-β-glucosamine asparagine amidase. These results unambiguously demonstrate that GlcNAc2 can be transferred from dolichol-PP-GlcNAc2 to one or both sequons of yeast Exg. Accordingly, they support previous observations suggesting that this early intermediate is able to translocate in vivo in order to make its sugar portion accessible to the oligosaccharyltransferase in the lumen of the endoplasmic reticulum. © 1998 John Wiley & Sons, Ltd.
Additional Material:
7 Ill.
Type of Medium:
Electronic Resource
