EC Number   |
Natural Substrates |
|---|
   6.3.1.19 | ATP + [prokaryotic ubiquitin-like protein]-L-glutamate + [proteasome-interacting ATPase]-L-lysine |
pupylation of proteasome-interacting ATPase (Mpa) occurs predominantly on one target lysine. Pupylation at this position prevents interaction of Mpa/prokaryotic ubiquitin-like protein(Pup) with the proteasome core. Ultimately, pupylation leads to deoligomerization of the Mpa hexamer driven by the unfolding activity of Mpa, thereby rendering Mpa-Pup fully inactive |
| 6.3.1.19 | ATP + [prokaryotic ubiquitin-like protein]-L-glutamate + [protein]-L-lysine |
- |
| 6.3.1.19 | ATP + [prokaryotic ubiquitin-like protein]-L-glutamate + [protein]-L-lysine |
key enzyme in the Pup tagging (i.e. pupylation) system. Protein pupylation can be regulated at the enzyme level via an allosteric mechanism |
| 6.3.1.19 | ATP + [prokaryotic ubiquitin-like protein]-L-glutamate + [protein]-L-lysine |
pupylation is a signal for proteasomal degradation in bacteria. The prokaryotic, ubiquitin-like protein (Pup) is conjugated through its C-terminal residue to lysine side chains of substrates via an isopeptide bond. Pup proteins are small, ranging from 60 to 70 residues in length with Gly-Gly-Glu or Gly-Gly-Gln as C-terminal residues. Deamidation of the C-terminal glutamine of Pup by the deamidase of Pup (Dop) renders Pup competent for conjugation to substrates, which is then carried out by the Pup-ligase PafA |
| 6.3.1.19 | ATP + [prokaryotic ubiquitin-like protein]-L-glutamate + [protein]-L-lysine |
pupylation targets the substrates for degradation by the proteasome |
| 6.3.1.19 | more |
PafA can pupylate itself, extra-pupylation by PafA can also occur, mostly in the form of poly-pupylation. Unlike in the eukaryotic UPS where poly-ubiquitylation is seen, in vivo targets of the Pup-proteasome system are found almost exclusively to be monopupylated, except for PafA itself. Poly-pupylation occurs via pupylation of an already pupylated target, rather than by conjugation of pre-formed poly-Pup chains |
