UniProt functional annotation for Q58576



	UniProt functional annotation for Q58576

UniProt code: Q58576.

Organism: Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) (Methanococcus jannaschii).

Taxonomy: Archaea; Euryarchaeota; Methanomada group; Methanococci; Methanococcales; Methanocaldococcaceae; Methanocaldococcus.

Function: ATPase which is responsible for recognizing, binding, unfolding and translocation of substrate proteins into the archaeal 20S proteasome core particle. Is essential for opening the gate of the 20S proteasome via an interaction with its C-terminus, thereby allowing substrate entry and access to the site of proteolysis. Thus, the C- termini of the proteasomal ATPase function like a 'key in a lock' to induce gate opening and therefore regulate proteolysis. Unfolding activity requires energy from ATP hydrolysis, whereas ATP binding alone promotes ATPase-20S proteasome association which triggers gate opening, and supports translocation of unfolded substrates. In addition to ATP, is able to cleave other nucleotide triphosphates such as CTP, GTP and UTP, but hydrolysis of these other nucleotides is less effective in promoting proteolysis than ATP. Moreover, PAN by itself can function as a chaperone in vitro. {ECO:0000255|HAMAP-Rule:MF_00553, ECO:0000269|PubMed:10473546, ECO:0000269|PubMed:10692374, ECO:0000269|PubMed:16337593, ECO:0000269|PubMed:17803938, ECO:0000269|PubMed:19481528}.

Activity regulation: ATPase activity is inhibited by EDTA, N- ethylmaleimide (NEM) and p-chloromercuriphenyl-sulfonic acid (PCMS) in vitro. {ECO:0000269|PubMed:10473546, ECO:0000269|PubMed:10692374}.

Biophysicochemical properties: Kinetic parameters: KM=497 uM for ATP {ECO:0000269|PubMed:10692374}; KM=307 uM for CTP {ECO:0000269|PubMed:10692374}; Vmax=3.5 umol/min/mg enzyme for ATPase activity {ECO:0000269|PubMed:10692374}; Vmax=5.8 umol/min/mg enzyme for CTPase activity {ECO:0000269|PubMed:10692374}; pH dependence: Optimum pH is 7-8 for ATPase activity. Is more active at pH 8 to 10 than at pH 5.5. {ECO:0000269|PubMed:10692374}; Temperature dependence: Optimum temperature is 80 degrees Celsius for ATPase activity. {ECO:0000269|PubMed:10692374};

Subunit: Homohexamer. The hexameric complex has a two-ring architecture resembling a top hat that caps the 20S proteasome core at one or both ends. Alone, can form a complex composed of two stacked hexameric rings in vitro. Upon ATP-binding, the C-terminus of PAN interacts with the alpha-rings of the proteasome core by binding to the intersubunit pockets. {ECO:0000269|PubMed:10692374, ECO:0000269|PubMed:16337593, ECO:0000269|PubMed:19481527, ECO:0000269|PubMed:20019667}.

Subcellular location: Cytoplasm.

Domain: Consists of three main regions, an N-terminal coiled-coil domain that may assist in substrate recognition, an interdomain involved in PAN hexamerization, and a C-terminal ATPase domain of the AAA type. {ECO:0000255|HAMAP-Rule:MF_00553, ECO:0000269|PubMed:19481527}.

Similarity: Belongs to the AAA ATPase family. {ECO:0000255|HAMAP- Rule:MF_00553}.

Annotations taken from UniProtKB at the EBI.


Organism:		Methanocaldococcus jannaschii (strain ATCC 43067 / DSM 2661 / JAL-1 / JCM 10045 / NBRC 100440) (Methanococcus jannaschii).
Taxonomy:		Archaea; Euryarchaeota; Methanomada group; Methanococci; Methanococcales; Methanocaldococcaceae; Methanocaldococcus.



Function:		ATPase which is responsible for recognizing, binding, unfolding and translocation of substrate proteins into the archaeal 20S proteasome core particle. Is essential for opening the gate of the 20S proteasome via an interaction with its C-terminus, thereby allowing substrate entry and access to the site of proteolysis. Thus, the C- termini of the proteasomal ATPase function like a 'key in a lock' to induce gate opening and therefore regulate proteolysis. Unfolding activity requires energy from ATP hydrolysis, whereas ATP binding alone promotes ATPase-20S proteasome association which triggers gate opening, and supports translocation of unfolded substrates. In addition to ATP, is able to cleave other nucleotide triphosphates such as CTP, GTP and UTP, but hydrolysis of these other nucleotides is less effective in promoting proteolysis than ATP. Moreover, PAN by itself can function as a chaperone in vitro. {ECO:0000255\|HAMAP-Rule:MF_00553, ECO:0000269\|PubMed:10473546, ECO:0000269\|PubMed:10692374, ECO:0000269\|PubMed:16337593, ECO:0000269\|PubMed:17803938, ECO:0000269\|PubMed:19481528}.


Activity regulation:		ATPase activity is inhibited by EDTA, N- ethylmaleimide (NEM) and p-chloromercuriphenyl-sulfonic acid (PCMS) in vitro. {ECO:0000269\|PubMed:10473546, ECO:0000269\|PubMed:10692374}.
Biophysicochemical properties:		Kinetic parameters: KM=497 uM for ATP {ECO:0000269\|PubMed:10692374}; KM=307 uM for CTP {ECO:0000269\|PubMed:10692374}; Vmax=3.5 umol/min/mg enzyme for ATPase activity {ECO:0000269\|PubMed:10692374}; Vmax=5.8 umol/min/mg enzyme for CTPase activity {ECO:0000269\|PubMed:10692374}; pH dependence: Optimum pH is 7-8 for ATPase activity. Is more active at pH 8 to 10 than at pH 5.5. {ECO:0000269\|PubMed:10692374}; Temperature dependence: Optimum temperature is 80 degrees Celsius for ATPase activity. {ECO:0000269\|PubMed:10692374};
Subunit:		Homohexamer. The hexameric complex has a two-ring architecture resembling a top hat that caps the 20S proteasome core at one or both ends. Alone, can form a complex composed of two stacked hexameric rings in vitro. Upon ATP-binding, the C-terminus of PAN interacts with the alpha-rings of the proteasome core by binding to the intersubunit pockets. {ECO:0000269\|PubMed:10692374, ECO:0000269\|PubMed:16337593, ECO:0000269\|PubMed:19481527, ECO:0000269\|PubMed:20019667}.
Subcellular location:		Cytoplasm.
Domain:		Consists of three main regions, an N-terminal coiled-coil domain that may assist in substrate recognition, an interdomain involved in PAN hexamerization, and a C-terminal ATPase domain of the AAA type. {ECO:0000255\|HAMAP-Rule:MF_00553, ECO:0000269\|PubMed:19481527}.
Similarity:		Belongs to the AAA ATPase family. {ECO:0000255\|HAMAP- Rule:MF_00553}.