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Q9V2V6 (PSA1_HALVD) Reviewed, UniProtKB/Swiss-Prot

Last modified June 11, 2014. Version 85. Feed History...

Clusters with 100%, 90%, 50% identity | Documents (2) | Third-party data text xml rdf/xml gff fasta
to top of pageNames·Attributes·General annotation·Ontologies·Sequence annotation·Sequences·References·Cross-refs·Entry info·DocumentsCustomize order

Names and origin

Protein namesRecommended name:
Proteasome subunit alpha 1

EC=3.4.25.1
Alternative name(s):
20S proteasome alpha subunit 1
Proteasome core protein PsmA 1
Gene names
Name:psmA1
Synonyms:psmA
Ordered Locus Names:HVO_1091
OrganismHaloferax volcanii (strain ATCC 29605 / DSM 3757 / JCM 8879 / NBRC 14742 / NCIMB 2012 / VKM B-1768 / DS2) (Halobacterium volcanii) [Reference proteome] [HAMAP]
Taxonomic identifier309800 [NCBI]
Taxonomic lineageArchaeaEuryarchaeotaHalobacteriaHalobacterialesHalobacteriaceaeHaloferax

Protein attributes

Sequence length252 AA.
Sequence statusComplete.
Sequence processingThe displayed sequence is further processed into a mature form.
Protein existenceEvidence at protein level

General annotation (Comments)

Function

Component of the proteasome core, a large protease complex with broad specificity involved in protein degradation. The H.volcanii alpha1-beta proteasome is able to cleave oligopeptides after Phe, Tyr and Trp, poorly after Glu but not after Arg. Thus, displays chymotrypsin-like activity, low caspase-like activity but no trypsin-like activity. Ref.1

Catalytic activity

Cleavage of peptide bonds with very broad specificity. Ref.1

Enzyme regulation

The formation of the proteasomal ATPase PAN-20S proteasome complex, via the docking of the C-termini of PAN into the intersubunit pockets in the alpha-rings, triggers opening of the gate for substrate entry. Interconversion between the open-gate and close-gate conformations leads to a dynamic regulation of the 20S proteasome proteolysis activity By similarity. In vitro, the chymotrypsin-like activity of the alpha1-beta proteasome is potently inhibited by carbobenzoxyl-leucinyl-leucinyl-leucinal-H (MG132) and significantly by N-acetyl-leucinyl-leucinyl-norleucinal-H (calpain inhibitor I). Ref.1

Subunit structure

The 20S proteasome core is composed of 14 alpha and 14 beta subunits that assemble into four stacked heptameric rings, resulting in a barrel-shaped structure. The two inner rings, each composed of seven catalytic beta subunits, are sandwiched by two outer rings, each composed of seven alpha subunits. H.volcanii produces at least 2 types of 20S proteasomes: an alpha1-beta proteasome and a proteasome containing all three subunits (alpha1, alpha2, and beta) that appears to be asymmetrical with homo-oligomeric alpha1 and alpha2 rings positioned on separate ends. The catalytic chamber with the active sites is on the inside of the barrel. Has probably a gated structure, the ends of the cylinder being occluded by the N-termini of the alpha-subunits. Is likely capped at one or both ends by the proteasome regulatory ATPase, PAN. Ref.1 Ref.3

Subcellular location

Cytoplasm By similarity HAMAP-Rule MF_00289.

Induction

Up-regulated at the mRNA level during transition from exponential to stationary phase. However, at the protein level, PsmA 1 is expressed at a high and relatively constant level throughout growth. Ref.1 Ref.4

Post-translational modification

Acetylated. The acetylated form at Met-1 was shown to be in 100-fold excess of the unacetylated form with the initiator methionine removed in whole cells and purified 20S proteasomes. Ref.5 Ref.7

Disruption phenotype

Strains lacking psmA1 gene alone display relatively normal growth rate and overall cell yield, but they are more sensitive to growth on organic versus inorganic nitrogen sources and hypo-osmotic stress, and they show limited growth in the presence of L-canavanine. Abolition of alpha1 subunit synthesis also has a severe impact on the ability of cells to withstand thermal stress. Moreover, depletion of psmA1 and psmA2 together renders the cells inviable. Ref.6

Miscellaneous

H.volcanii proteasome requires high concentrations of salt, similar to the extracellular environment and cytoplasm of this organism, for complex stability and optimal activity.

Sequence similarities

Belongs to the peptidase T1A family.

Biophysicochemical properties

pH dependence:

Optimum pH is 7.0-9.3 for the Suc-LLVY-Amc hydrolyzing activity (with the alpha1-beta proteasome subtype). Ref.1

Temperature dependence:

Optimum temperature is 75 degrees Celsius for the Suc-LLVY-Amc hydrolyzing activity (with the alpha1-beta proteasome subtype).

Sequence annotation (Features)

Feature keyPosition(s)LengthDescriptionGraphical viewFeature identifier

Molecule processing

Chain1 – 252252Proteasome subunit alpha 1 HAMAP-Rule MF_00289
PRO_0000124171
Initiator methionine11Removed; alternate Ref.5
Chain2 – 252251Proteasome subunit alpha 1, N-terminally processed HAMAP-Rule MF_00289
PRO_0000397604

Amino acid modifications

Modified residue11N-acetylmethionine; alternate Ref.5

Experimental info

Mutagenesis2 – 1211Missing: Prevents acetylation of Met-1. Enhances peptidase activity of the proteasome. Renders the cells less tolerant of hypoosmotic stress than the wild-type. Ref.7
Mutagenesis21Q → A: Enhances cleavage of PsmA1 by methionine aminopeptidase (MAP), resulting in acetylation of the N-terminal alanine. Enhances peptidase activity of the proteasome. Renders the cells less tolerant of hypoosmotic stress than the wild-type. Ref.7
Mutagenesis21Q → D, P or T: Does not alter the prevalence of the alpha1 subunit in N-acetylated form in proteasomes. Renders the cells more tolerant of hypoosmotic and high-temperature stress than the wild-type. Ref.7
Sequence conflict961R → H in AAD53404. Ref.1

Sequences

Sequence LengthMass (Da)Tools
Q9V2V6 [UniParc].

Last modified July 13, 2010. Version 2.
Checksum: 500A2DCCB0B71C71

FASTA25227,613
        10         20         30         40         50         60 
MQGQAQQQAY DRGITIFSPD GRLYQVEYAR EAVKRGTASI GVRTPEGVVL AADKRSRSPL 

        70         80         90        100        110        120 
MEPTSVEKIH KADDHIGIAS AGHVADARQL IDFARRQSQV NRLRYGEPIG IETLTKEVTD 

       130        140        150        160        170        180 
HIQQYTQVGG ARPFGVALLI GGVENGTPRL YETDPSGTPY EWKAVSIGAD RGDHQEHLEE 

       190        200        210        220        230        240 
NFRDDLTLDE GIELALEAIA STSDEGTAPD GVDVATVSAE TERFVELSND EIESYLEAND 

       250 
LLATEDDEQT EE 

« Hide

References

« Hide 'large scale' references
[1]"Halophilic 20S proteasomes of the archaeon Haloferax volcanii: purification, characterization, and gene sequence analysis."
Wilson H.L., Aldrich H.C., Maupin-Furlow J.
J. Bacteriol. 181:5814-5824(1999) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [GENOMIC DNA], PROTEIN SEQUENCE OF 23-30; 89-95 AND 150-163, BLOCKAGE OF N-TERMINUS, FUNCTION, CATALYTIC ACTIVITY, SUBSTRATE SPECIFICITY, BIOPHYSICOCHEMICAL PROPERTIES, ENZYME REGULATION, SALT REQUIREMENT, SUBUNIT.
[2]"The complete genome sequence of Haloferax volcanii DS2, a model archaeon."
Hartman A.L., Norais C., Badger J.H., Delmas S., Haldenby S., Madupu R., Robinson J., Khouri H., Ren Q., Lowe T.M., Maupin-Furlow J., Pohlschroder M., Daniels C., Pfeiffer F., Allers T., Eisen J.A.
PLoS ONE 5:E9605-E9605(2010) [PubMed] [Europe PMC] [Abstract]
Cited for: NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
Strain: ATCC 29605 / DSM 3757 / JCM 8879 / NBRC 14742 / NCIMB 2012 / VKM B-1768 / DS2.
[3]"Subunit topology of two 20S proteasomes from Haloferax volcanii."
Kaczowka S.J., Maupin-Furlow J.A.
J. Bacteriol. 185:165-174(2003) [PubMed] [Europe PMC] [Abstract]
Cited for: SUBUNIT.
[4]"Differential regulation of the PanA and PanB proteasome-activating nucleotidase and 20S proteasomal proteins of the haloarchaeon Haloferax volcanii."
Reuter C.J., Kaczowka S.J., Maupin-Furlow J.A.
J. Bacteriol. 186:7763-7772(2004) [PubMed] [Europe PMC] [Abstract]
Cited for: INDUCTION.
[5]"Posttranslational modification of the 20S proteasomal proteins of the archaeon Haloferax volcanii."
Humbard M.A., Stevens S.M. Jr., Maupin-Furlow J.A.
J. Bacteriol. 188:7521-7530(2006) [PubMed] [Europe PMC] [Abstract]
Cited for: ACETYLATION AT MET-1, CLEAVAGE OF INITIATOR METHIONINE.
[6]"Proteasomal components required for cell growth and stress responses in the haloarchaeon Haloferax volcanii."
Zhou G., Kowalczyk D., Humbard M.A., Rohatgi S., Maupin-Furlow J.A.
J. Bacteriol. 190:8096-8105(2008) [PubMed] [Europe PMC] [Abstract]
Cited for: DISRUPTION PHENOTYPE.
[7]"The N-terminal penultimate residue of 20S proteasome alpha1 influences its N(alpha) acetylation and protein levels as well as growth rate and stress responses of Haloferax volcanii."
Humbard M.A., Zhou G., Maupin-Furlow J.A.
J. Bacteriol. 191:3794-3803(2009) [PubMed] [Europe PMC] [Abstract]
Cited for: ACETYLATION, MUTAGENESIS OF GLN-2 AND 2-GLN--ARG-12.

Cross-references

Sequence databases

EMBL
GenBank
DDBJ
AF126260 Genomic DNA. Translation: AAD53404.1.
CP001956 Genomic DNA. Translation: ADE04430.1.
PIRT48678.
RefSeqYP_003535146.1. NC_013967.1.

3D structure databases

ModBaseSearch...
MobiDBSearch...

Protocols and materials databases

StructuralBiologyKnowledgebaseSearch...

Genome annotation databases

EnsemblBacteriaADE04430; ADE04430; HVO_1091.
GeneID8925549.
KEGGhvo:HVO_1091.

Phylogenomic databases

HOGENOMHOG000091085.
KOK03432.
OMAFQVNYAR.

Enzyme and pathway databases

BioCycHVOL309800:GCOK-1095-MONOMER.

Family and domain databases

Gene3D3.60.20.10. 1 hit.
HAMAPMF_00289_A. Proteasome_A_A.
InterProIPR029055. Ntn_hydrolases_N.
IPR019982. Proteasome_asu_arc.
IPR000426. Proteasome_asu_N.
IPR023332. Proteasome_suA-type.
IPR001353. Proteasome_sua/b.
[Graphical view]
PfamPF00227. Proteasome. 1 hit.
PF10584. Proteasome_A_N. 1 hit.
[Graphical view]
SMARTSM00948. Proteasome_A_N. 1 hit.
[Graphical view]
SUPFAMSSF56235. SSF56235. 1 hit.
TIGRFAMsTIGR03633. arc_protsome_A. 1 hit.
PROSITEPS00388. PROTEASOME_ALPHA_1. 1 hit.
PS51475. PROTEASOME_ALPHA_2. 1 hit.
[Graphical view]
ProtoNetSearch...

Entry information

Entry namePSA1_HALVD
AccessionPrimary (citable) accession number: Q9V2V6
Secondary accession number(s): D4GW11
Entry history
Integrated into UniProtKB/Swiss-Prot: December 8, 2000
Last sequence update: July 13, 2010
Last modified: June 11, 2014
This is version 85 of the entry and version 2 of the sequence. [Complete history]
Entry statusReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Relevant documents

SIMILARITY comments

Index of protein domains and families

Peptidase families

Classification of peptidase families and list of entries