Sandbox Reserved 381: Difference between revisions
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O-GlcNAc modification has been described for a large and still increasing number of proteins, many of which are key modulators of cellular signalling. O-GlcNAc modifications are catalysed by a OGT, and are removed by the antagonistic enzyme B-N-acetylglucosaminidase (O-GlcNAcase). The general scheme of O-linked N-acetylglucosamine modification suggests that N-acetylglucosamine is added to serine/threonine (Ser/Thr) residues of target proteins by the enzyme OGT using UDP-GlcNAc as substrate. The N-acetylglucosamine group is removed by the antagonistic activity of O-GlcNAcase. <ref>Alexander G, Danilo G. The O-linked N-acetylglucosamine modification in cellular signalling and the immune system. EMBO reports. 2008 June;9:748-753[http://www.nature.com/embor/journal/v9/n8/full/embor2008129.html]</ref> | O-GlcNAc modification has been described for a large and still increasing number of proteins, many of which are key modulators of cellular signalling. O-GlcNAc modifications are catalysed by a OGT, and are removed by the antagonistic enzyme B-N-acetylglucosaminidase (O-GlcNAcase). The general scheme of O-linked N-acetylglucosamine modification suggests that N-acetylglucosamine is added to serine/threonine (Ser/Thr) residues of target proteins by the enzyme OGT using UDP-GlcNAc as substrate. The N-acetylglucosamine group is removed by the antagonistic activity of O-GlcNAcase. <ref>Alexander G, Danilo G. The O-linked N-acetylglucosamine modification in cellular signalling and the immune system. EMBO reports. 2008 June;9:748-753[http://www.nature.com/embor/journal/v9/n8/full/embor2008129.html]</ref> | ||
== OGT Features of Interest == | |||
OGT is the only known member to glycosylate polypeptides and it contains a long uncharacterized intervening sequence (~120 amino acids) in the middle of the catalytic region. Studies suggest that OGT contains a phosphatidylinositol (3,4,5)-trisphosphate (PIP3)binding domain. The most unusual feature of OGT is the intervening domain between the catalytic lobes, which is only found in metazoans. This polypeptide adopts a topologically novel fold with a seven-stranded <scene name='Sandbox_Reserved_381/Ogt_structure/1'>beta</scene> sheet core stabilized by flanking alpha helices. There are two long unstructured loops for which electron density is missing.<ref> PMID:18288188</ref> | |||
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<Structure load='1W3B' size='300' frame='true' align='left' caption='Superhelical TPR Domain of OGT' scene='N-Terminus Region' /> | <Structure load='1W3B' size='300' frame='true' align='left' caption='Superhelical TPR Domain of OGT' scene='N-Terminus Region' /> | ||
