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Protein

DNA polymerase III subunit tau

Gene

dnaX

Organism
Escherichia coli (strain K12)
Status
Reviewed-Annotation score: Annotation score: 5 out of 5-Experimental evidence at protein leveli

Functioni

Part of the beta sliding clamp loading complex, which hydrolyzes ATP to load the beta clamp onto primed DNA to form the DNA replication pre-initiation complex (PubMed:2040637). DNA polymerase III is a complex, multichain enzyme responsible for most of the replicative synthesis in bacteria. This DNA polymerase also exhibits 3'-5' exonuclease activity. The gamma complex (gamma3,delta,delta') is thought to load beta dimers onto DNA by binding ATP which alters the complex's conformation so it can bind beta sliding clamp dimers and open them at one interface. Primed DNA is recognized, ATP is hydrolyzed releasing the gamma complex and closing the beta sliding clamp ring around the primed DNA (PubMed:9927437).1 Publication
Isoform tau: serves as a scaffold to trimerize the core complex (PubMed:7037770).1 Publication
Isoform gamma: interacts with the delta and delta' subunits to transfer the beta subunit on the DNA (PubMed:9927437). Interacts with ATP, drives ATP-induced conformational changes in the gamma complex that opens the beta sliding clamp ring. After loading of primed DNA ATP is hydrolyzed and the beta sliding clamp ring closes (PubMed:9927437).1 Publication

Catalytic activityi

Deoxynucleoside triphosphate + DNA(n) = diphosphate + DNA(n+1).

Regions

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Nucleotide bindingi45 – 52ATPSequence analysis8

GO - Molecular functioni

  • ATPase activity Source: EcoliWiki
  • ATP binding Source: UniProtKB-KW
  • DNA binding Source: InterPro
  • DNA-directed DNA polymerase activity Source: UniProtKB-KW
  • DNA polymerase processivity factor activity Source: EcoliWiki
  • identical protein binding Source: IntAct
  • nucleoside-triphosphatase activity Source: EcoliWiki

GO - Biological processi

  • DNA-dependent DNA replication Source: GO_Central
  • DNA replication Source: EcoliWiki

Keywordsi

Molecular functionDNA-directed DNA polymerase, Nucleotidyltransferase, Transferase
Biological processDNA replication
LigandATP-binding, Nucleotide-binding

Enzyme and pathway databases

BioCyciEcoCyc:EG10245-MONOMER.
EcoCyc:MONOMER0-2383.
MetaCyc:EG10245-MONOMER.
MetaCyc:MONOMER0-2383.

Names & Taxonomyi

Protein namesi
Recommended name:
DNA polymerase III subunit tau (EC:2.7.7.7)
Alternative name(s):
DNA polymerase III subunit gamma
Gene namesi
Name:dnaX
Synonyms:dnaZ, dnaZX
Ordered Locus Names:b0470, JW0459
OrganismiEscherichia coli (strain K12)
Taxonomic identifieri83333 [NCBI]
Taxonomic lineageiBacteriaProteobacteriaGammaproteobacteriaEnterobacteralesEnterobacteriaceaeEscherichia
Proteomesi
  • UP000000318 Componenti: Chromosome
  • UP000000625 Componenti: Chromosome

Organism-specific databases

EcoGeneiEG10245. dnaX.

Subcellular locationi

GO - Cellular componenti

  • DNA polymerase III, clamp loader complex Source: EcoliWiki

Pathology & Biotechi

Mutagenesis

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Mutagenesisi118G → D in dnaX2016(Ts); present in both isoforms, unable to grow at 42 degrees Celsius. 1 Publication1
Mutagenesisi601E → K in dnaX36(Ts); present only in isoform tau, unable to grow at 42 degrees Celsius. 1 Publication1

Chemistry databases

DrugBankiDB02930. Phosphothiophosphoric Acid-Adenylate Ester.

PTM / Processingi

Molecule processing

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Initiator methionineiRemoved
ChainiPRO_00000073602 – 643DNA polymerase III subunit tauAdd BLAST642

Proteomic databases

PaxDbiP06710.
PRIDEiP06710.

Interactioni

Subunit structurei

The DNA polymerase III holoenzyme complex contains at least 10 different subunits organized into 3 functionally essential subassemblies: the Pol III core, the beta sliding clamp processivity factor and the clamp-loading complex. The Pol III core (subunits alpha, epsilon and theta) contains the polymerase and the 3'-5' exonuclease proofreading activities (PubMed:2040637). The polymerase is tethered to the template via the dimeric beta sliding clamp processivity factor. The clamp-loading complex (also called gamma complex) assembles the beta sliding clamp onto the primed template and plays a central role in the organization and communication at the replication fork. The clamp-loading complex contains delta, delta', psi and chi, and 3 copies of either or both of two different DnaX proteins, gamma and tau. The DNA replisome complex has a single clamp loader (3 tau and 1 each of delta, delta', psi and chi subunits) which binds 3 Pol III cores (1 core on the leading strand and 2 on the lagging strand) each with a beta sliding clamp dimer. Additional proteins in the replisome are other copies of gamma, psi and chi, Ssb, DNA helicase and RNA primase (PubMed:20413500, PubMed:22157955). The clamp loader hydrolyzes ATP to assemble the beta processivity factor onto the primed template (PubMed:2040637, PubMed:9927437) and plays a central role in the organization and communication at the replication fork; the minimal complex to load the beta sliding clamp on DNA is delta, delta', gamma (PubMed:9927437).5 Publications

Binary interactionsi

Show more details

GO - Molecular functioni

  • identical protein binding Source: IntAct

Protein-protein interaction databases

BioGridi4259846. 114 interactors.
DIPiDIP-9464N.
IntActiP06710. 33 interactors.
MINTiMINT-1222776.
STRINGi316385.ECDH10B_0426.

Chemistry databases

BindingDBiP06710.

Structurei

Secondary structure

1643
Legend: HelixTurnBeta strandPDB Structure known for this area
Show more details
Feature keyPosition(s)DescriptionActionsGraphical viewLength
Helixi6 – 9Combined sources4
Helixi15 – 17Combined sources3
Helixi22 – 34Combined sources13
Beta strandi39 – 44Combined sources6
Beta strandi46 – 50Combined sources5
Helixi51 – 63Combined sources13
Helixi77 – 83Combined sources7
Beta strandi88 – 94Combined sources7
Turni95 – 97Combined sources3
Helixi98 – 100Combined sources3
Helixi101 – 109Combined sources9
Beta strandi111 – 113Combined sources3
Beta strandi116 – 126Combined sources11
Helixi128 – 130Combined sources3
Helixi133 – 144Combined sources12
Beta strandi150 – 157Combined sources8
Helixi159 – 161Combined sources3
Helixi164 – 167Combined sources4
Beta strandi170 – 174Combined sources5
Helixi180 – 193Combined sources14
Helixi200 – 210Combined sources11
Helixi214 – 225Combined sources12
Turni226 – 229Combined sources4
Beta strandi230 – 232Combined sources3
Helixi234 – 240Combined sources7
Helixi248 – 257Combined sources10
Helixi261 – 274Combined sources14
Helixi278 – 294Combined sources17
Turni295 – 297Combined sources3
Helixi299 – 301Combined sources3
Turni304 – 306Combined sources3
Helixi307 – 318Combined sources12
Helixi322 – 338Combined sources17
Turni339 – 341Combined sources3
Beta strandi342 – 344Combined sources3
Helixi345 – 358Combined sources14
Beta strandi361 – 363Combined sources3
Helixi507 – 520Combined sources14
Helixi522 – 530Combined sources9
Helixi535 – 541Combined sources7
Beta strandi543 – 547Combined sources5
Beta strandi549 – 556Combined sources8
Helixi558 – 560Combined sources3
Turni561 – 563Combined sources3
Helixi566 – 580Combined sources15
Beta strandi585 – 590Combined sources6
Helixi599 – 620Combined sources22

3D structure databases

Select the link destinations:
PDBei
RCSB PDBi
PDBji
Links Updated
PDB entryMethodResolution (Å)ChainPositionsPDBsum
1JR3X-ray2.70A/B/C1-373[»]
1NJFX-ray2.30A/B/C/D1-243[»]
1NJGX-ray2.20A/B1-243[»]
1XXHX-ray3.45B/C/D/G/H/I1-373[»]
1XXIX-ray4.10B/C/D/G/H/I1-368[»]
2AYANMR-A499-625[»]
3GLFX-ray3.39B/C/D/G/H/I1-373[»]
3GLGX-ray3.25B/C/D/G/H/I1-373[»]
3GLHX-ray3.89B/C/D/G/H/I/L/M/N1-373[»]
3GLIX-ray3.50B/C/D/G/H/I1-373[»]
5FKUelectron microscopy8.34E500-643[»]
5FKVelectron microscopy8.00E500-643[»]
ProteinModelPortaliP06710.
SMRiP06710.
ModBaseiSearch...
MobiDBiSearch...

Miscellaneous databases

EvolutionaryTraceiP06710.

Family & Domainsi

Sequence similaritiesi

Belongs to the DnaX/STICHEL family.Curated

Phylogenomic databases

eggNOGiENOG4107QMP. Bacteria.
COG2812. LUCA.
HOGENOMiHOG000083934.
InParanoidiP06710.
KOiK02343.
PhylomeDBiP06710.

Family and domain databases

InterProiView protein in InterPro
IPR003593. AAA+_ATPase.
IPR001270. ClpA/B.
IPR008921. DNA_pol3_clamp-load_cplx_C.
IPR022001. DNA_pol3_tau_IV.
IPR022754. DNA_pol_III_gamma-3.
IPR012763. DNA_pol_III_sug/sutau.
IPR021029. DNA_pol_III_tau_dom-5.
IPR027417. P-loop_NTPase.
PfamiView protein in Pfam
PF12169. DNA_pol3_gamma3. 1 hit.
PF12168. DNA_pol3_tau_4. 1 hit.
PF12170. DNA_pol3_tau_5. 1 hit.
PRINTSiPR00300. CLPPROTEASEA.
SMARTiView protein in SMART
SM00382. AAA. 1 hit.
SUPFAMiSSF48019. SSF48019. 1 hit.
SSF52540. SSF52540. 1 hit.
TIGRFAMsiTIGR02397. dnaX_nterm. 1 hit.

Sequences (2)i

Sequence statusi: Complete.

Sequence processingi: The displayed sequence is further processed into a mature form.

This entry describes 2 isoformsi produced by ribosomal frameshifting. AlignAdd to basket

Note: The production of the two protein products from this region is due to programmed ribosomal frameshifting. Frameshifting is about 40% efficient.3 Publications
Isoform tau (identifier: P06710-1) [UniParc]FASTAAdd to basket

This isoform has been chosen as the 'canonical' sequence. All positional information in this entry refers to it. This is also the sequence that appears in the downloadable versions of the entry.

« Hide

        10         20         30         40         50
MSYQVLARKW RPQTFADVVG QEHVLTALAN GLSLGRIHHA YLFSGTRGVG
60 70 80 90 100
KTSIARLLAK GLNCETGITA TPCGVCDNCR EIEQGRFVDL IEIDAASRTK
110 120 130 140 150
VEDTRDLLDN VQYAPARGRF KVYLIDEVHM LSRHSFNALL KTLEEPPEHV
160 170 180 190 200
KFLLATTDPQ KLPVTILSRC LQFHLKALDV EQIRHQLEHI LNEEHIAHEP
210 220 230 240 250
RALQLLARAA EGSLRDALSL TDQAIASGDG QVSTQAVSAM LGTLDDDQAL
260 270 280 290 300
SLVEAMVEAN GERVMALINE AAARGIEWEA LLVEMLGLLH RIAMVQLSPA
310 320 330 340 350
ALGNDMAAIE LRMRELARTI PPTDIQLYYQ TLLIGRKELP YAPDRRMGVE
360 370 380 390 400
MTLLRALAFH PRMPLPEPEV PRQSFAPVAP TAVMTPTQVP PQPQSAPQQA
410 420 430 440 450
PTVPLPETTS QVLAARQQLQ RVQGATKAKK SEPAAATRAR PVNNAALERL
460 470 480 490 500
ASVTDRVQAR PVPSALEKAP AKKEAYRWKA TTPVMQQKEV VATPKALKKA
510 520 530 540 550
LEHEKTPELA AKLAAEAIER DPWAAQVSQL SLPKLVEQVA LNAWKEESDN
560 570 580 590 600
AVCLHLRSSQ RHLNNRGAQQ KLAEALSMLK GSTVELTIVE DDNPAVRTPL
610 620 630 640
EWRQAIYEEK LAQARESIIA DNNIQTLRRF FDAELDEESI RPI
Note: Produced by full-length translation of the dnaX gene. This isoform is essential, constructs that express only the gamma isoform are not viable (PubMed:8376347).1 Publication
Length:643
Mass (Da):71,138
Last modified:January 1, 1988 - v1
Checksum:iD2028BD99E375150
GO
Isoform gamma (identifier: P06710-2) [UniParc]FASTAAdd to basket

The sequence of this isoform differs from the canonical sequence as follows:
     431-431: S → E
     432-643: Missing.

Note: Formed by programmed ribosomal frameshifting to a premature stop codon in the -1 frame at codon 430, the last residue is thus Glu and not Ser. Mutants which remove the frameshift are viable, suggesting strongly that gamma is not essential for viability (PubMed:8376347).4 Publications
Show »
Length:431
Mass (Da):47,545
Checksum:i8177A07F31BC86E3
GO

Sequence cautioni

The sequence CAA28175 differs from that shown. Reason: Erroneous initiation. Translation N-terminally extended.Curated

Alternative sequence

Feature keyPosition(s)DescriptionActionsGraphical viewLength
Alternative sequenceiVSP_042848431S → E in isoform gamma. Curated1
Alternative sequenceiVSP_042849432 – 643Missing in isoform gamma. CuratedAdd BLAST212

Sequence databases

Select the link destinations:
EMBLi
GenBanki
DDBJi
Links Updated
X04487 Genomic DNA. Translation: CAA28174.1.
X04487 Genomic DNA. Translation: CAA28175.1. Different initiation.
X04275 Genomic DNA. Translation: CAA27827.1.
U82664 Genomic DNA. Translation: AAB40224.1.
U00096 Genomic DNA. Translation: AAC73572.1.
AP009048 Genomic DNA. Translation: BAE76249.1.
M38777 Genomic DNA. Translation: AAA23457.1.
PIRiA25549. DJEC3G.
RefSeqiNP_415003.1. NC_000913.3.
WP_000122013.1. NZ_LN832404.1.

Genome annotation databases

EnsemblBacteriaiAAC73572; AAC73572; b0470.
BAE76249; BAE76249; BAE76249.
GeneIDi945105.
KEGGiecj:JW0459.
eco:b0470.
PATRICifig|1411691.4.peg.1806.

Keywords - Coding sequence diversityi

Ribosomal frameshifting

Similar proteinsi

Entry informationi

Entry nameiDPO3X_ECOLI
AccessioniPrimary (citable) accession number: P06710
Secondary accession number(s): Q2MBV7, Q47721
Entry historyiIntegrated into UniProtKB/Swiss-Prot: January 1, 1988
Last sequence update: January 1, 1988
Last modified: August 30, 2017
This is version 173 of the entry and version 1 of the sequence. See complete history.
Entry statusiReviewed (UniProtKB/Swiss-Prot)
Annotation programProkaryotic Protein Annotation Program

Miscellaneousi

Keywords - Technical termi

3D-structure, Complete proteome, Direct protein sequencing, Reference proteome

Documents

  1. Escherichia coli
    Escherichia coli (strain K12): entries and cross-references to EcoGene
  2. PDB cross-references
    Index of Protein Data Bank (PDB) cross-references
  3. SIMILARITY comments
    Index of protein domains and families