Molecule of the Month: Sulfotransferases
Sulfotransferases transfer sulfuryl groups in enzymatic reactions
Sulfonation in the Cytoplasm
...and in the Golgi
An Exceptional Enzyme
Sulfotransferase mSULT1D1 (PDB entry 2zyv)
Most sulfotransferases transfer sulfuryl groups from PAPS to their target molecules. PAPS is a
very convenient molecule for this task, because it carries an activated form of the sulfuryl group,
and it also contains several phosphoryl groups that are easy to recognize and bind in the
active site. The structure shown on the left (PDB entry
contains PAPS bound to a
mouse sulfotransferase, along with two molecules that are ready to accept sulfuryl groups.
The bacterial enzyme shown on the right uses a different mechanism. It performs the
reaction in two steps. First, the sulfuryl group is transferred from a phenol carrier to a histidine
amino acid in the enzyme, then, it is transferred from the protein to the target
molecule. This structure (PDB entry
has captured the enzyme in the middle of this
process, with the sulfuryl group attached to the histidine.
You can use the "Ligand Explorer" to look at the interaction of sulfotransferase amino acids with PAPS and other ligands. Click here for an example.
Topics for Further Discussion
- Many examples of cytosolic sulfotransferases are available in the PDB. Use the Ligand Explorer to look for differences in the active sites that explain their different substrate preferences.
- The active site of many sulfotransferases is buried inside the protein, covered by a flexible loop of protein. Notice that this loop is disordered in many sulfotransferase structures, and is typically only seen when there are substrates bound in the active site.
Related PDB-101 Resources
- Browse Enzymes
- E. Chapman, M. D. Best, S. R. Hanson and C. H. Wong (2004) Sulfotransferases: structure, mechanism, biological activity, inhibition and synthetic utility. Angewandte Chemie 43, 3526-3548.
- N. Gamage, A. Barnett, N. Hempel, R. G. Duggleby, K. F. Windmill, J. L. Martin and M. E. McManus (2006) Human sulfotransferases and their role in chemical metabolism. Toxicological Sciences 90, 5-22.
- J. Liu and L. C. Pedersen (2007) Anticoagulant heparan sulfate: structural specificity and biosynthesis. Applied Microbiology and Biotechnology 74, 263-272.
- G. Malojcic, R. L. Owen, J. P. A. Grimshaw, M. S. Brozzo, H. Dreher-Teo and R. Glockshuber (2008) A structural and biochemical basis for PAPS-independent sulfuryl transfer by aryl sulfotransferase from uropathogenic Escherichia coli. Proceedings of the National Academy of Sciences USA 105, 19217-19222.
August 2009, David Goodsellhttp://doi.org/10.2210/rcsb_pdb/mom_2009_8