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The efficiency of N-linked glycosylation of bovine DNase I depends on the Asn-Xaa-Ser/Thr sequence and the tissue of origin.

ABSTRACT: Bovine DNase I contains two potential N-linked glycosylation sites with the sequences Asn(18)-Ala-Thr and Asn(106)-Asp-Ser. A previous report established that pancreatic DNase I has only one sugar chain at Asn(18) [Liao, Salnikow, Moore and Stein (1973) J. Biol. Chem. 248, 1489-1495]. We found, however, that bovine DNase I expressed in COS-1 cells was glycosylated about 70% at Asn(106) in addition to being completely glycosylated at Asn(18). Glycosylation of Asn(106) increased to 97% when Asp(107) was mutated to Glu or when Ser(108) was mutated to Thr. Mutation of Asp(107) to Trp had no effect, whereas a substitution with Pro at this position abolished glycosylation of Asn(106). Analysis of the state of glycosylation of DNase I purified from a variety of bovine tissues revealed that DNase I from spleen, submaxillary gland, lung and adrenal had two sugar chains, whereas enzyme from pancreas and kidney had only one sugar chain. These findings demonstrate a major difference in the ability of various tissues to utilize N-linked glycosylation signals that contain suboptimal residues in the second and third positions.

SUBMITTER: Nishikawa A

PROVIDER: S-EPMC1221733 | biostudies-other | 2001 Apr

REPOSITORIES: biostudies-other

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Regulation of N-linked core glycosylation: use of a site-directed mutagenesis approach to identify Asn-Xaa-Ser/Thr sequons that are poor oligosaccharide acceptors.

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The role of the hydroxy amino acid in the triplet sequence Asn-Xaa-Thr(Ser) for the N-glycosylation step during glycoprotein biosynthesis.

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