Importance of N-glycosylation positioning for secretion and folding of ovalbumin.
To investigate the role of the carbohydrate chain of hen egg ovalbumin (OVA), potential N-glycosylation site-deletion OVA mutants were expressed in yeast. The secretion level of the N292Q and N292/311Q mutants was greatly reduced compared with the wild-type OVA. Furthermore, secretion of the mutants without a carbohydrate chain on Asn-292 could hardly be detected in the culture medium, even if an additional N-glycosylation site was introduced to the OVA molecule. The reduction in secretion level seems to be due to incorrectly folded protein. Moreover, the secretion levels of the wild-type and N311Q mutant reduced in a similar extent as those of the mutants without a carbohydrate chain on Asn-292 in calnexin-disrupted yeast. These results indicate that the carbohydrate chain attached to Asn-292 of OVA has an important role for the secretion and folding in the cells.
Department of Biological Chemistry, Faculty of Agriculture, Yamaguchi University, Yamaguchi 753-8515, Japan.
Kazunari
K
Ito
Takayuki
T
Ishimaru
Fukiko
F
Kimura
Naotoshi
N
Matsudomi
D000818:Animals; D001216:Asparagine / Q000378:metabolism; D037281:Calnexin / Q000378:metabolism; D002645:Chickens; D006031:Glycosylation; D008957:Models, Genetic; D010047:Ovalbumin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010843:Pichia / Q000235:genetics / Q000378:metabolism; D017510:Protein Folding; D011499:Protein Processing, Post-Translational; D012441:Saccharomyces cerevisiae / Q000378:metabolism
D037281:Calnexin; D001216:Asparagine; D010047:Ovalbumin