10.6084/m9.figshare.5110273.v1 Karim Rafie Karim Rafie Olawale Raimi Olawale Raimi Andrew T. Ferenbach Andrew T. Ferenbach Vladimir S. Borodkin Vladimir S. Borodkin Vaibhav Kapuria Vaibhav Kapuria Daan M. F. van Aalten Daan M. F. van Aalten Figure S1 from Recognition of a glycosylation substrate by the O-GlcNAc transferase TPR repeats The Royal Society 2017 glycosylation signalling O-GlcNAc O-GlcNAc transferase substrate recognition 2017-06-15 05:31:54 Journal contribution https://rs.figshare.com/articles/journal_contribution/Figure_S1_from_Recognition_of_a_glycosylation_substrate_by_the_O-GlcNAc_transferase_TPR_repeats/5110273 O-linked <i>N</i>-acetylglucosamine (O-GlcNAc) is an essential and dynamic post-translational modification found on hundreds of nucleocytoplasmic proteins in metazoa. Although a single enzyme, O-GlcNAc transferase (OGT), generates the entire cytosolic O-GlcNAc proteome, it is not understood how it recognizes its protein substrates, targeting only a fraction of serines/threonines in the metazoan proteome for glycosylation. We describe a trapped complex of human OGT with the C-terminal domain of TAB1, a key innate immunity signalling O-GlcNAc protein, revealing extensive interactions with the tetratricopeptide repeats of OGT. Confirmed by mutagenesis, this interaction suggests that glycosylation substrate specificity is achieved by recognition of a degenerate sequon in the active site combined with an extended conformation C-terminal of the O-GlcNAc target site.