Identifier |
Residue |
Sequence |
Organism |
Cell Line |
SIGNOR-177694 |
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Homo sapiens |
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pmid |
sentence |
22117070 |
We have previously identified two human genes, gxylt1 and gxylt2, encoding glucoside xylosyltransferases responsible for the transfer of xylose to o-linked glucose. The identity of the enzyme further elongating the glycan to generate the final trisaccharide xylose-xylose-glucose, however, remained unknown. Here, we describe that the human gene c3orf21 encodes a udp-xylose:alfa-xyloside alfa1,3-xylosyltransferase, acting on xylose-alfa1,3-glucosebeta1-containing acceptor structures. We have, therefore, renamed it xxylt1 (xyloside xylosyltransferase 1). Xxylt1 cannot act on a synthetic acceptor containing an alfa-linked xylose alone, but requires the presence of the underlying glucose. Activity on notch egf repeats was proven by in vitro xylosylation of a mouse notch1 fragment recombinantly produced in sf9 insect cells, a bacterially expressed egf repeat from mouse notch2 modified in vitro by rumi and gxylt2 and in vivo by co-expression of the enzyme with the notch1 fragment. The enzyme was shown to be a typical type ii membrane-bound glycosyltransferase localized in the endoplasmic reticulum. |
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