Cloned (Comment) | Organism |
---|---|
recombinant expression of FLAG-tagged wild-type and mutant subunits Rpt3 and Rpt6 in HeLa cells | Homo sapiens |
Protein Variants | Comment | Organism |
---|---|---|
additional information | disruption of nucleotide binding to an Rpt subunit by mutation in the Walker A motif, mutation in the Walker B motif, deletion of the HbYX motif, C-terminal deletions in Rpts not possessing the HbYX motif | Homo sapiens |
Metals/Ions | Comment | Organism | Structure |
---|---|---|---|
Mg2+ | required | Homo sapiens |
Natural Substrates | Organism | Comment (Nat. Sub.) | Natural Products | Comment (Nat. Pro.) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + H2O + polypeptide | Homo sapiens | - |
ADP + phosphate + unfolded polypeptide | - |
? |
Organism | UniProt | Comment | Textmining |
---|---|---|---|
Homo sapiens | - |
- |
- |
Substrates | Comment Substrates | Organism | Products | Comment (Products) | Rev. | Reac. |
---|---|---|---|---|---|---|
ATP + H2O + polypeptide | - |
Homo sapiens | ADP + phosphate + unfolded polypeptide | - |
? |
Temperature Optimum [°C] | Temperature Optimum Maximum [°C] | Comment | Organism |
---|---|---|---|
37 | - |
assay at | Homo sapiens |
pH Optimum Minimum | pH Optimum Maximum | Comment | Organism |
---|---|---|---|
7.2 | - |
assay at | Homo sapiens |
General Information | Comment | Organism |
---|---|---|
malfunction | disruption of nucleotide binding to an Rpt subunit by mutation in the Walker A motif inhibits the assembly of the Rpt ring without affecting heterodimer formation with its partner Rpt subunit. Coexpression of the base assembly chaperones S5b and PAAF1 with mutant Rpt1 and Rpt6, respectively, relieves assembly inhibition of mutant Rpts by facilitating their interaction with adjacent Rpt dimers. The mutation in the Walker B motif which impairs ATP hydrolysis does not affect Rpt ring formation. Incorporation of a Walker B mutant Rpt subunit abrogates the ATPase activity of the 19S RP, suggesting that failure of the mutant Rpt to undergo the conformational transition from an ATP-bound to an ADP-bound state impairs conformational changes in the other five wild-type Rpts in the Rpt ring. Deletion of the HbYX motif impairs the efficient assembly of the ATPase ring in the 19S RP, whereas C-terminal deletions in Rpts not possessing the HbYX motif do not have any deleterious effect on proteasome assembly | Homo sapiens |
additional information | assembly of the 26S proteasome is a complex process involving formation of ring structures from homologous subunits. Stable incorporation of ATPase subunits into 19S regulatory particle, RP, of human proteasome requires nucleotide binding and C-terminal tails, but not ATP hydrolysis. The C-terminal tails of Rpt subunits possessing core particle (CP)-binding affinities facilitate the cellular assembly of the 19S RP, implying that the 20S core particle may function as a template for base assembly in human cells | Homo sapiens |