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Escherichia coli K-12 substr. MG1655 Enzyme: deoxyguanosine triphosphate triphosphohydrolase



Gene: dgt Accession Numbers: EG10225 (EcoCyc), b0160, ECK0159

Synonyms: optA

Regulation Summary Diagram: ?

Subunit composition of deoxyguanosine triphosphate triphosphohydrolase = [Dgt]4
         deoxyguanosine triphosphate triphosphohydrolase = Dgt

Summary:
Deoxyguanosinetriphosphate triphosphohydrolase (dGTPase, Dgt) is a unique nucleoside triphosphatase which hydrolyzes dGTP to deoxyguanosine and inorganic tripolyphosphate [Kornberg58, Seto88]. Possible physiological roles of the enzyme have only recently been elucidated. Dgt may be involved in replication fidelity via its effect on the cellular pool of dGTP [Gawel08]. The level of Dgt expression correlates with the ability of cells to salvage thymine in the absence of functional de novo biosynthesis in a thyA mutant, presumably due to its effect on the intracellular deoxyribose-1-phosphate pool [Itsko11].

dGTPase is able to bind single-stranded DNA with relatively high affinity [Wurgler93].

The optA1 allele of dgt, a promoter mutation [Wurgler90], causes increased production of dGTPase, which makes the cells unable to support growth of phage T7 containing mutations in gene 1.2 [Beauchamp88]. The wild-type gene 1.2 protein is a specific inhibitor of dGTPase by binding to the enzyme [Huber88, Nakai90].

A dgt null mutation has no detectable growth phenotype in rich medium [Wurgler90]. Several dgt transposon insertion mutants were shown to have a mutator phenotype [Gawel08].

OptA: [Saito81a]

Dgt: "dGTPase" [Quirk89]

Citations: [Quirk90, Degryse91]

Locations: cytosol

Map Position: [179,237 -> 180,754] (3.86 centisomes)
Length: 1518 bp / 505 aa

Molecular Weight of Polypeptide: 59.383 kD (from nucleotide sequence), 58.9 kD (experimental) [Seto88 ]

Molecular Weight of Multimer: 230.0 kD (experimental) [Seto88]

pI: 7.48

Unification Links: ASAP:ABE-0000548 , CGSC:30546 , DIP:DIP-9437N , EchoBASE:EB0221 , EcoGene:EG10225 , EcoliWiki:b0160 , Mint:MINT-1223226 , OU-Microarray:b0160 , PortEco:dgt , PR:PRO_000022437 , Pride:P15723 , Protein Model Portal:P15723 , RefSeq:NP_414702 , RegulonDB:EG10225 , SMR:P15723 , String:511145.b0160 , UniProt:P15723

Relationship Links: InterPro:IN-FAMILY:IPR003607 , InterPro:IN-FAMILY:IPR006261 , InterPro:IN-FAMILY:IPR006674 , InterPro:IN-FAMILY:IPR020779 , InterPro:IN-FAMILY:IPR023293 , InterPro:IN-FAMILY:IPR027432 , Pfam:IN-FAMILY:PF01966 , Smart:IN-FAMILY:SM00471

Gene-Reaction Schematic: ?

GO Terms:

Biological Process: GO:0006184 - GTP catabolic process Inferred from experiment [Seto88]
GO:0015949 - nucleobase-containing small molecule interconversion Inferred from experiment [Seto88]
GO:0043099 - pyrimidine deoxyribonucleoside salvage Inferred from experiment [Itsko11]
GO:0006203 - dGTP catabolic process Inferred by computational analysis [GOA01]
GO:0046039 - GTP metabolic process Inferred by computational analysis [GOA01]
Molecular Function: GO:0003697 - single-stranded DNA binding Inferred from experiment [Wurgler93]
GO:0003924 - GTPase activity Inferred from experiment [Seto88]
GO:0008832 - dGTPase activity Inferred from experiment Inferred by computational analysis [GOA01a, GOA01, Kornberg58, Beauchamp88]
GO:0030145 - manganese ion binding Inferred from experiment [Seto88]
GO:0050897 - cobalt ion binding Inferred from experiment [Seto88]
GO:0000287 - magnesium ion binding Inferred by computational analysis [GOA01]
GO:0016787 - hydrolase activity Inferred by computational analysis [UniProtGOA11]
Cellular Component: GO:0005737 - cytoplasm
GO:0005829 - cytosol Inferred by computational analysis [DiazMejia09]

MultiFun Terms: metabolism central intermediary metabolism nucleotide and nucleoside conversions

Essentiality data for dgt knockouts: ?

Growth Medium Growth? T (°C) O2 pH Osm/L Growth Observations
LB enriched Yes 37 Aerobic 6.95   Yes [Gerdes03, Comment 1]
LB Lennox Yes 37 Aerobic 7   Yes [Baba06, Comment 2]
M9 medium with 1% glycerol Yes 37 Aerobic 7.2 0.35 Yes [Joyce06, Comment 3]
MOPS medium with 0.4% glucose Yes 37 Aerobic 7.2 0.22 Yes [Baba06, Comment 2]
Yes [Feist07, Comment 4]

Credits:
Last-Curated ? 13-Jul-2011 by Keseler I , SRI International


Enzymatic reaction of: deoxyguanosine triphosphate triphosphohydrolase

Synonyms: dGTPase, deoxy-GTPase, deoxyguanosine-PPP PPP-hydrolase, dGTP triphosphohydrolase

EC Number: 3.1.5.1

dGTP + H2O <=> PPPi + 2'-deoxyguanosine + H+

The reaction direction shown, that is, A + B ↔ C + D versus C + D ↔ A + B, is in accordance with the direction of enzyme catalysis.

The reaction is irreversible in the direction shown.

Alternative Substrates for dGTP [Comment 5 ]: GTP [Seto88 ]

Cofactors or Prosthetic Groups: Mg2+ [Comment 6, Seto88]

Inhibitors (Competitive): GTP [Kornberg58]

Inhibitors (Unknown Mechanism): GDP [Kornberg58]

Kinetic Parameters:

Substrate
Km (μM)
kcat (sec-1)
kcat/Km (sec-1 μM-1)
Citations
GTP
150.0
[Kornberg58]
dGTP
2.0
[Beauchamp88, BRENDA14]
dGTP
2.5
[Kornberg58]
dGTP
1.0
4000.0
[Seto88, BRENDA14]


Sequence Features

Feature Class Location Citations Comment
Cleavage-of-Initial-Methionine 1
[Seto88, UniProt11]
UniProt: Removed.
Chain 2 -> 505
[UniProt09]
UniProt: Deoxyguanosinetriphosphate triphosphohydrolase;
Sequence-Conflict 363
[Quirk90, UniProt10a]
Alternate sequence: T → R; UniProt: (in Ref. 2; AAA23716);
Sequence-Conflict 450
[Quirk90, UniProt10a]
Alternate sequence: R → P; UniProt: (in Ref. 2; AAA23716);


Gene Local Context (not to scale): ?

Transcription Units:

Notes:

History:
10/20/97 Gene b0160 from Blattner lab Genbank (v. M52) entry merged into EcoCyc gene EG10225; confirmed by SwissProt match.


References

Baba06: Baba T, Ara T, Hasegawa M, Takai Y, Okumura Y, Baba M, Datsenko KA, Tomita M, Wanner BL, Mori H (2006). "Construction of Escherichia coli K-12 in-frame, single-gene knockout mutants: the Keio collection." Mol Syst Biol 2;2006.0008. PMID: 16738554

Beauchamp88: Beauchamp BB, Richardson CC (1988). "A unique deoxyguanosine triphosphatase is responsible for the optA1 phenotype of Escherichia coli." Proc Natl Acad Sci U S A 85(8);2563-7. PMID: 2833745

BRENDA14: BRENDA team (2014). "Imported from BRENDA version existing on Aug 2014." http://www.brenda-enzymes.org.

Degryse91: Degryse E (1991). "Polymorphism in the dgt-dapD-tsf region of Escherichia coli K-12 strains." Gene 102(1);141-2. PMID: 1677906

DiazMejia09: Diaz-Mejia JJ, Babu M, Emili A (2009). "Computational and experimental approaches to chart the Escherichia coli cell-envelope-associated proteome and interactome." FEMS Microbiol Rev 33(1);66-97. PMID: 19054114

Feist07: Feist AM, Henry CS, Reed JL, Krummenacker M, Joyce AR, Karp PD, Broadbelt LJ, Hatzimanikatis V, Palsson BO (2007). "A genome-scale metabolic reconstruction for Escherichia coli K-12 MG1655 that accounts for 1260 ORFs and thermodynamic information." Mol Syst Biol 3;121. PMID: 17593909

Gawel08: Gawel D, Hamilton MD, Schaaper RM (2008). "A novel mutator of Escherichia coli carrying a defect in the dgt gene, encoding a dGTP triphosphohydrolase." J Bacteriol 190(21);6931-9. PMID: 18776019

Gerdes03: Gerdes SY, Scholle MD, Campbell JW, Balazsi G, Ravasz E, Daugherty MD, Somera AL, Kyrpides NC, Anderson I, Gelfand MS, Bhattacharya A, Kapatral V, D'Souza M, Baev MV, Grechkin Y, Mseeh F, Fonstein MY, Overbeek R, Barabasi AL, Oltvai ZN, Osterman AL (2003). "Experimental determination and system level analysis of essential genes in Escherichia coli MG1655." J Bacteriol 185(19);5673-84. PMID: 13129938

GOA01: GOA, DDB, FB, MGI, ZFIN (2001). "Gene Ontology annotation through association of InterPro records with GO terms."

GOA01a: GOA, MGI (2001). "Gene Ontology annotation based on Enzyme Commission mapping." Genomics 74;121-128.

Huber88: Huber HE, Beauchamp BB, Richardson CC (1988). "Escherichia coli dGTP triphosphohydrolase is inhibited by gene 1.2 protein of bacteriophage T7." J Biol Chem 263(27);13549-56. PMID: 2843524

Itsko11: Itsko M, Schaaper RM (2011). "The dgt gene of Escherichia coli facilitates thymine utilization in thymine-requiring strains." Mol Microbiol 81(5);1221-32. PMID: 21736641

Joyce06: Joyce AR, Reed JL, White A, Edwards R, Osterman A, Baba T, Mori H, Lesely SA, Palsson BO, Agarwalla S (2006). "Experimental and computational assessment of conditionally essential genes in Escherichia coli." J Bacteriol 188(23);8259-71. PMID: 17012394

Kornberg58: Kornberg SR, Lehman IR, Bessman MJ, Simms ES, Kornberg A (1958). "Enzymatic cleavage of deoxyguanosine triphosphate to deoxyguanosine and tripolyphosphate." J Biol Chem 1958; 233:159-162. PMID: 13563461

Nakai90: Nakai H, Richardson CC (1990). "The gene 1.2 protein of bacteriophage T7 interacts with the Escherichia coli dGTP triphosphohydrolase to form a GTP-binding protein." J Biol Chem 265(8);4411-9. PMID: 2155228

Quirk89: Quirk S, Seto D, Bhatnagar SK, Gauss P, Gold L, Bessman MJ (1989). "Location and molecular cloning of the structural gene for the deoxyguanosine triphosphate triphosphohydrolase of Escherichia coli." Mol Microbiol 3(10);1391-5. PMID: 2559296

Quirk90: Quirk S, Bhatnagar SK, Bessman MJ (1990). "Primary structure of the deoxyguanosine triphosphate triphosphohydrolase-encoding gene (dgt) of Escherichia coli." Gene 1990;89(1);13-8. PMID: 2165018

Saito81a: Saito H, Richardson CC (1981). "Genetic analysis of gene 1.2 of bacteriophage T7: isolation of a mutant of Escherichia coli unable to support the growth of T7 gene 1.2 mutants." J Virol 37(1);343-51. PMID: 7012382

Seto88: Seto D, Bhatnagar SK, Bessman MJ (1988). "The purification and properties of deoxyguanosine triphosphate triphosphohydrolase from Escherichia coli." J Biol Chem 1988;263(3);1494-9. PMID: 2826481

UniProt09: UniProt Consortium (2009). "UniProt version 15.8 released on 2009-10-01 00:00:00." Database.

UniProt10a: UniProt Consortium (2010). "UniProt version 2010-11 released on 2010-11-02 00:00:00." Database.

UniProt11: UniProt Consortium (2011). "UniProt version 2011-06 released on 2011-06-30 00:00:00." Database.

UniProtGOA11: UniProt-GOA (2011). "Gene Ontology annotation based on manual assignment of UniProtKB keywords in UniProtKB/Swiss-Prot entries."

Wurgler90: Wurgler SM, Richardson CC (1990). "Structure and regulation of the gene for dGTP triphosphohydrolase from Escherichia coli." Proc Natl Acad Sci U S A 87(7);2740-4. PMID: 2157212

Wurgler93: Wurgler SM, Richardson CC (1993). "DNA binding properties of the deoxyguanosine triphosphate triphosphohydrolase of Escherichia coli." J Biol Chem 268(27);20046-54. PMID: 8397198

Other References Related to Gene Regulation

Kim06c: Kim Y, Lew CM, Gralla JD (2006). "Escherichia coli pfs transcription: regulation and proposed roles in autoinducer-2 synthesis and purine excretion." J Bacteriol 188(21);7457-63. PMID: 16950920


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Please cite the following article in publications resulting from the use of EcoCyc: Nucleic Acids Research 41:D605-12 2013
Page generated by SRI International Pathway Tools version 18.5 on Sun Dec 21, 2014, biocyc13.