Gene Ontology annotation through association of InterPro records with GO terms
Use of the ND evidence code for Gene Ontology (GO) terms
Annotation inferences using phylogenetic trees
Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt
Electronic Gene Ontology annotations created by ARBA machine learning models
Combined Automated Annotation using Multiple IEA Methods
Mnt2p and Mnt3p of Saccharomyces cerevisiae are members of the Mnn1p family of alpha-1,3-mannosyltransferases responsible for adding the terminal mannose residues of O-linked oligosaccharides.
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The S. cerevisiae genome encodes five type II transmembrane proteins similar to the alpha-1,3-mannosyltransferase Mnn1p, establishing the MNN1/MNT family that contains MNT4.
"The genome of Saccharomyces cerevisiae contains five genes that encode type II transmembrane proteins with significant amino acid similarity to the alpha-1,3-mannosyltransferase Mnn1p."
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MNT2 and MNT3 (with MNN1) add the fourth and fifth alpha-1,3-mannose residues of O-linked oligosaccharides, whereas MNT4 is not required for O-glycan synthesis - the one MNT4-specific functional (negative) result.
"the MNT2 (YGL257c) and MNT3 (YIL014w) genes in combination with MNN1 have overlapping roles in the addition of the fourth and fifth alpha-1,3-linked mannose residues to form Man4 and Man5 oligosaccharides whereas MNT4 (YNR059w) does not appear to be required for O-glycan synthesis."
Activity of the yeast MNN1 alpha-1,3-mannosyltransferase requires a motif conserved in many other families of glycosyltransferases.
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A conserved two-aspartate (DxD) motif is essential for Mnn1p alpha-1,3-mannosyltransferase catalytic activity; this motif appears intact in MNT4.
"altering either of these aspartates eliminates all enzymatic activity"