Molecule of the Month: O-GlcNAc Transferase
Some protein functions are regulated when sugars are attached
Just Add Sugar
Exploring the Structure
O-GlcNAc Transferase (PDB entries 3pe4, 1w3b and 2jlb)
By combining three different structures, you can take a look at the reaction performed by O-GlcNAc transferase. PDB entry 3pe4 contains the catalytic domain and part of the protein-recognizing domain, and PDB entry 1w3b contains most of the protein-recognizing domain. Fortunately, there is a little overlap between the two, so you can do a superposition to simulate the whole protein. The structure in entry 3pe4 also includes a peptide and UDP bound in the active site. To see where the sugar binds in UDP-GlcNAc, you can look at the structure of a similar enzyme from bacteria, from PDB entry 2jlb . Click on the image here to see an interactive Jmol of these three structures.
Topics for Further Discussion
- Structures are available for several other bacterial GlcNAcase-like enzymes, for instance, in PDB entry 2chn. You can overlap these structures and look for similarities using "Compare Structures" tools.
- O-GlcNAc transferase and GlcNAcase are both targets for drug development, because of their connection to diabetes. In the PDB, you can find several structures of these enzymes with inhibitors.
September 2011, David Goodsellhttp://doi.org/10.2210/rcsb_pdb/mom_2011_9