Gene Symbol: spoT
Description: bifunctional (p)ppGpp synthetase II/ guanosine-3',5'-bis pyrophosphate 3'-pyrophosphohydrolase
Alias: ECK3640, JW3625
Species: Escherichia coli str. K-12 substr. MG1655

Top Publications

  1. Terui Y, Akiyama M, Sakamoto A, Tomitori H, Yamamoto K, Ishihama A, et al. Increase in cell viability by polyamines through stimulation of the synthesis of ppGpp regulatory protein and ? protein of RNA polymerase in Escherichia coli. Int J Biochem Cell Biol. 2012;44:412-22 pubmed publisher
    ..It was found that the synthesis of ppGpp regulatory protein (SpoT) and ? protein of RNA polymerase (RpoZ) was stimulated by polyamines at the level of translation...
  2. Mechold U, Murphy H, Brown L, Cashel M. Intramolecular regulation of the opposing (p)ppGpp catalytic activities of Rel(Seq), the Rel/Spo enzyme from Streptococcus equisimilis. J Bacteriol. 2002;184:2878-88 pubmed
    ..These assignments can also apply to RelA and SpoT. The ability of Rel(Seq) to mediate (p)ppGpp accumulation during amino acid starvation in S...
  3. Sajish M, Kalayil S, Verma S, Nandicoori V, Prakash B. The significance of EXDD and RXKD motif conservation in Rel proteins. J Biol Chem. 2009;284:9115-23 pubmed publisher
  4. Gentry D, Cashel M. Mutational analysis of the Escherichia coli spoT gene identifies distinct but overlapping regions involved in ppGpp synthesis and degradation. Mol Microbiol. 1996;19:1373-84 pubmed
    The spoT gene of Escherichia coli encodes a guanosine 3',5'-bis(diphosphate) 3'-pyrophosphohydrolase (ppGppase) as well as an apparent guanosine 3',5'-bis(diphosphate) synthetase (designated PSII)...
  5. Hogg T, Mechold U, Malke H, Cashel M, Hilgenfeld R. Conformational antagonism between opposing active sites in a bifunctional RelA/SpoT homolog modulates (p)ppGpp metabolism during the stringent response [corrected]. Cell. 2004;117:57-68 pubmed
    ..Reciprocal regulation of the antagonistic catalytic activities, suggested by the structure, is supported by mutagenesis experiments and appears to involve ligand-induced signal transmission between the two active sites...
  6. Magnusson L, Farewell A, Nystrom T. ppGpp: a global regulator in Escherichia coli. Trends Microbiol. 2005;13:236-42 pubmed
    ..In addition, new insights into the mechanism by which ppGpp affects gene expression have been achieved owing to in vitro studies of ppGpp function, complemented by structural studies of the ppGpp-RNA polymerase complex. ..
  7. Barker M, Gaal T, Josaitis C, Gourse R. Mechanism of regulation of transcription initiation by ppGpp. I. Effects of ppGpp on transcription initiation in vivo and in vitro. J Mol Biol. 2001;305:673-88 pubmed
    ..The accompanying paper evaluates potential models for positive control of amino acid promoters by ppGpp that might explain the requirement of ppGpp for amino acid prototrophy. ..
  8. Wendrich T, Blaha G, Wilson D, Marahiel M, Nierhaus K. Dissection of the mechanism for the stringent factor RelA. Mol Cell. 2002;10:779-88 pubmed
  9. Wout P, Pu K, Sullivan S, Reese V, Zhou S, Lin B, et al. The Escherichia coli GTPase CgtAE cofractionates with the 50S ribosomal subunit and interacts with SpoT, a ppGpp synthetase/hydrolase. J Bacteriol. 2004;186:5249-57 pubmed
    ..Interestingly, CgtA(E) copurifies with SpoT, a ribosome-associated ppGpp hydrolase/synthetase involved in the stress response...

More Information


  1. Battesti A, Bouveret E. Acyl carrier protein/SpoT interaction, the switch linking SpoT-dependent stress response to fatty acid metabolism. Mol Microbiol. 2006;62:1048-63 pubmed
    ..In Escherichia coli, upon fatty acid or carbon starvation, SpoT enzyme activity switches from (p)ppGpp degradation to (p)ppGpp synthesis, but the signal and mechanism for this ..
  2. Sarubbi E, Rudd K, Cashel M. Basal ppGpp level adjustment shown by new spoT mutants affect steady state growth rates and rrnA ribosomal promoter regulation in Escherichia coli. Mol Gen Genet. 1988;213:214-22 pubmed
    ..A series of strains was derived by mutating the spoT gene (which encodes the major cellular ppGppase) so as to obtain systematic increments in ppGpp basal levels...
  3. Jiang M, Sullivan S, Wout P, Maddock J. G-protein control of the ribosome-associated stress response protein SpoT. J Bacteriol. 2007;189:6140-7 pubmed
    The bacterial response to stress is controlled by two proteins, RelA and SpoT. RelA generates the alarmone (p)ppGpp under amino acid starvation, whereas SpoT is responsible for (p)ppGpp hydrolysis and for synthesis of (p)ppGpp under a ..
  4. Xiao H, Kalman M, Ikehara K, Zemel S, Glaser G, Cashel M. Residual guanosine 3',5'-bispyrophosphate synthetic activity of relA null mutants can be eliminated by spoT null mutations. J Biol Chem. 1991;266:5980-90 pubmed
    ..cellular degradation of ppGpp is mainly due to a manganese-dependent ppGpp 3'-pyrophosphohydrolase encoded by the spoT gene...
  5. Srivatsan A, Wang J. Control of bacterial transcription, translation and replication by (p)ppGpp. Curr Opin Microbiol. 2008;11:100-5 pubmed publisher
    ..In Escherichia coli, the enzymes RelA and SpoT are triggered by different starvation signals to produce (p)ppGpp...
  6. Potrykus K, Cashel M. (p)ppGpp: still magical?. Annu Rev Microbiol. 2008;62:35-51 pubmed publisher
    ..Many basic questions still exist. This review tries to focus on some issues that linger even for the most widely characterized bacterial strains. ..
  7. Bougdour A, Gottesman S. ppGpp regulation of RpoS degradation via anti-adaptor protein IraP. Proc Natl Acad Sci U S A. 2007;104:12896-901 pubmed
    ..Sensing of phosphate starvation requires SpoT but not RelA...
  8. Traxler M, Summers S, Nguyen H, Zacharia V, Hightower G, Smith J, et al. The global, ppGpp-mediated stringent response to amino acid starvation in Escherichia coli. Mol Microbiol. 2008;68:1128-48 pubmed publisher
    ..starvation for isoleucine, which could be applied to both wild-type Escherichia coli and the multiauxotrophic relA spoT mutant (ppGpp(0)). We used microarrays to profile the response to amino acid starvation in both strains...
  9. Yamada A, Tsutsumi K, Tanimoto S, Ozeki Y. Plant RelA/SpoT homolog confers salt tolerance in Escherichia coli and Saccharomyces cerevisiae. Plant Cell Physiol. 2003;44:3-9 pubmed
    ..A transformant expressing RelA/SpoT homolog (Sj-RSH) was found to have enhanced salt tolerance. In E...
  10. Suthers P, Gourse R, Yin J. Rapid responses of ribosomal RNA synthesis to nutrient shifts. Biotechnol Bioeng. 2007;97:1230-45 pubmed
    ..Inclusion of DksA was essential in all three cases. Our work provides a foundation for using data-driven computational models to predict the kinetics of in vivo transcriptional responses. ..
  11. Hernandez V, Bremer H. Guanosine tetraphosphate (ppGpp) dependence of the growth rate control of rrnB P1 promoter activity in Escherichia coli. J Biol Chem. 1990;265:11605-14 pubmed
    ..A series of spoT strains differing in the severity of their SpoT defect were analyzed with respect to their growth characteristics ..
  12. Belitskiĭ B, Shakulov R. [Role of spot gene product in the degradation of pppGpp in bacteria]. Mol Biol (Mosk). 1982;16:857-64 pubmed
    ..In E. coli phenanthroline inactivates the product of spoT gene, which is responsible for ppGpp degradation, as a result of combining Mn2+ ions necessary for the activity of ..
  13. Gong L, Takayama K, Kjelleberg S. Role of spoT-dependent ppGpp accumulation in the survival of light-exposed starved bacteria. Microbiology. 2002;148:559-70 pubmed publisher
    ..This study describes the involvement of SpoT-mediated ppGpp accumulation in the survival of light-exposed bacteria during fatty acid starvation...
  14. Lemke J, Durfee T, Gourse R. DksA and ppGpp directly regulate transcription of the Escherichia coli flagellar cascade. Mol Microbiol. 2009;74:1368-79 pubmed publisher
  15. Heinemeyer E, Richter D. In vitro degradation of guanosine tetraphosphate (ppGpp) by an enzyme associated with the ribosomal fraction from Escherichia coli. FEBS Lett. 1977;84:357-61 pubmed
  16. Guido N, Lee P, Wang X, Elston T, Collins J. A pathway and genetic factors contributing to elevated gene expression noise in stationary phase. Biophys J. 2007;93:L55-7 pubmed
    ..Endogenous cellular mechanisms that globally affect gene expression noise, such as those identified in this study, could provide phenotypic diversity under adverse conditions such as stationary phase. ..
  17. Aberg A, Shingler V, Balsalobre C. (p)ppGpp regulates type 1 fimbriation of Escherichia coli by modulating the expression of the site-specific recombinase FimB. Mol Microbiol. 2006;60:1520-33 pubmed
    ..Our findings suggest that the (p)ppGpp-stimulated expression of type 1 fimbriae may be relevant during the interaction of pathogenic E. coli with the host. ..
  18. Maitra A, Shulgina I, Hernandez V. Conversion of active promoter-RNA polymerase complexes into inactive promoter bound complexes in E. coli by the transcription effector, ppGpp. Mol Cell. 2005;17:817-29 pubmed
  19. Ferullo D, Lovett S. The stringent response and cell cycle arrest in Escherichia coli. PLoS Genet. 2008;4:e1000300 pubmed publisher
    ..This is the first indication that bacterial chromosome segregation, whose mechanism is not understood, is a step that may be regulated in response to environmental conditions. ..
  20. Fiil N, Willumsen B, Friesen J, von Meyenburg K. Interaction of alleles of the relA, relC and spoT genes in Escherichia coli: analysis of the interconversion of GTP, ppGpp and pppGpp. Mol Gen Genet. 1977;150:87-101 pubmed
    ..The entry of 3H-guanosine into GTP and ppGpr pools in spoT+ and spoT1 cells either growing exponentially or during amino acid starvation was determined, and the rate of ppGpp ..
  21. Boehm A, Steiner S, Zaehringer F, Casanova A, Hamburger F, Ritz D, et al. Second messenger signalling governs Escherichia coli biofilm induction upon ribosomal stress. Mol Microbiol. 2009;72:1500-16 pubmed publisher
    ..Treatment with translation inhibitors causes a ppGpp hydrolase (SpoT)-mediated reduction of ppGpp levels, resulting in specific derepression of PgaA...
  22. Zhang X, Liang S, Bremer H. Feedback control of ribosome synthesis in Escherichia coli is dependent on eight critical amino acids. Biochimie. 2006;88:1145-55 pubmed
    ..We suggest that addition of any of the eight critical amino acids reduces the ppGpp synthesis activity of the spoT gene product; the lower ppGpp levels, in turn, increase the strength of the rrn P1 promoters...
  23. Gralla J. Escherichia coli ribosomal RNA transcription: regulatory roles for ppGpp, NTPs, architectural proteins and a polymerase-binding protein. Mol Microbiol. 2005;55:973-7 pubmed
    ..This review discusses the current state of affairs, including recent information about the involvement of two nucleotide regulators, two architectural protein regulators, one new co-regulator and stalled ribosomes. ..
  24. Jones P, Cashel M, Glaser G, Neidhardt F. Function of a relaxed-like state following temperature downshifts in Escherichia coli. J Bacteriol. 1992;174:3903-14 pubmed
    ..Finally, shifting a relA spoT mutant, which cannot synthesize (p)ppGpp, from 24 to 10 degrees C resulted in a greater induction of the cold shock ..
  25. Nakanishi N, Abe H, Ogura Y, Hayashi T, Tashiro K, Kuhara S, et al. ppGpp with DksA controls gene expression in the locus of enterocyte effacement (LEE) pathogenicity island of enterohaemorrhagic Escherichia coli through activation of two virulence regulatory genes. Mol Microbiol. 2006;61:194-205 pubmed publisher
    ..The activation was dependent on relA and spoT, which encode enzymes for the synthesis and degradation of ppGpp, and on dksA, which encodes an RNA polymerase ..
  26. Vinella D, Albrecht C, Cashel M, D Ari R. Iron limitation induces SpoT-dependent accumulation of ppGpp in Escherichia coli. Mol Microbiol. 2005;56:958-70 pubmed
    ..We show that inactivation of the fes gene causes iron limitation on rich medium plates and a parallel SpoT-dependent increase of the ppGpp pool, as judged by the induction of the iron-regulated fiu::lacZ fusion and the ..
  27. Asato Y. Control of ribosome synthesis during the cell division cycles of E. coli and Synechococcus. Curr Issues Mol Biol. 2005;7:109-17 pubmed
    ..These observations suggest that gene regulatory proteins are involved in the coordinate regulation of ribosome assembly in Synechococcus. ..
  28. Schneider D, Gourse R. Changes in the concentrations of guanosine 5'-diphosphate 3'-diphosphate and the initiating nucleoside triphosphate account for inhibition of rRNA transcription in fructose-1,6-diphosphate aldolase (fda) mutants. J Bacteriol. 2003;185:6192-4 pubmed
  29. Kalman M, Murphy H, Cashel M. The nucleotide sequence of recG, the distal spo operon gene in Escherichia coli K-12. Gene. 1992;110:95-9 pubmed
    ..genes in the spo operon were spoS, alias rpoZ, encoding the omega (omega) subunit of RNA polymerase, as well as the spoT gene encoding the major cellular source of guanosine 3',5'-bispyrophosphate hydrolase activity...
  30. Aberg A, Fernández Vázquez J, Cabrer Panes J, Sanchez A, Balsalobre C. Similar and divergent effects of ppGpp and DksA deficiencies on transcription in Escherichia coli. J Bacteriol. 2009;191:3226-36 pubmed publisher
    ..coli. ..
  31. Cooper T, Rozen D, Lenski R. Parallel changes in gene expression after 20,000 generations of evolution in Escherichiacoli. Proc Natl Acad Sci U S A. 2003;100:1072-7 pubmed
    ..Sequencing of several genes controlling the effectors of these regulons found a nonsynonymous mutation in spoT in one population...
  32. Fujita C, Nishimura A, Iwamoto R, Ikehara K. Guanosine 5'-diphosphate 3'-diphosphate (ppGpp) synthetic activities on Escherichia coli SpoT domains. Biosci Biotechnol Biochem. 2002;66:1515-23 pubmed
    Escherichia coli SpoT protein, with 702 amino acid residues, is a bifunctional enzyme catalyzing both guanosine 5'-diphosphate 3'-diphosphate (ppGpp) degradation and its synthesis...
  33. Heinemeyer E, Geis M, Richter D. Degradation of guanosine 3'-diphosphate 5'-diphosphate in vitro by the spoT gene product of Escherichia coli. Eur J Biochem. 1978;89:125-31 pubmed
    ..5'-diphosphate (ppG) and probably pyrophosphate by an enzyme present in the ribosomal fraction prepared from spoT+ strains of Escherichia coli...
  34. Kvint K, Farewell A, Nystrom T. RpoS-dependent promoters require guanosine tetraphosphate for induction even in the presence of high levels of sigma(s). J Biol Chem. 2000;275:14795-8 pubmed
  35. Barker M, Gaal T, Gourse R. Mechanism of regulation of transcription initiation by ppGpp. II. Models for positive control based on properties of RNAP mutants and competition for RNAP. J Mol Biol. 2001;305:689-702 pubmed
    Strains containing ppGpp, a nucleotide whose synthesis is dependent on the RelA and SpoT proteins of Escherichia coli, display slightly lower rRNA promoter activity and much higher amino acid biosynthesis/transport promoter activity than ..
  36. Kuhar I, van Putten J, Zgur Bertok D, Gaastra W, Jordi B. Codon-usage based regulation of colicin K synthesis by the stress alarmone ppGpp. Mol Microbiol. 2001;41:207-16 pubmed
    ..Nutrient starvation experiments and the use of relA spoT mutant strains, IPTG-regulated overproduction of ppGpp and lacZ fusions revealed that the stringent response ..
  37. Bremer H, Dennis P. Feedback control of ribosome function in Escherichia coli. Biochimie. 2008;90:493-9 pubmed
    ..37 degrees C), the feedback signal ppGpp is generated by an activation of the ppGpp synthetase expressed from the spoT gene...
  38. Battesti A, Bouveret E. Bacteria possessing two RelA/SpoT-like proteins have evolved a specific stringent response involving the acyl carrier protein-SpoT interaction. J Bacteriol. 2009;191:616-24 pubmed publisher
    ..In Escherichia coli, RelA produces (p)ppGpp upon amino acid starvation by detecting stalled ribosomes. The SpoT enzyme responds to various other types of starvation by unknown mechanisms...
  39. Hernandez V, Bremer H. Escherichia coli ppGpp synthetase II activity requires spoT. J Biol Chem. 1991;266:5991-9 pubmed
    ..Genetic mapping by phage P1 transduction and complementation analyses showed that the mutations were located in spoT and that they were recessive...
  40. Gaal T, Gourse R. Guanosine 3'-diphosphate 5'-diphosphate is not required for growth rate-dependent control of rRNA synthesis in Escherichia coli. Proc Natl Acad Sci U S A. 1990;87:5533-7 pubmed
    ..Recently, relA- spoT- strains have been constructed in which both ppGpp synthesis pathways most likely have been removed (M...
  41. Montero M, Rahimpour M, Viale A, Almagro G, Eydallin G, Sevilla Ã, et al. Systematic production of inactivating and non-inactivating suppressor mutations at the relA locus that compensate the detrimental effects of complete spot loss and affect glycogen content in Escherichia coli. PLoS ONE. 2014;9:e106938 pubmed publisher
    ..are controlled by the balanced activities of the ppGpp RelA synthetase and the dual-function hydrolase/synthetase SpoT. Here we report the construction of spoT null (ΔspoT) mutants obtained by transducing a ΔspoT allele from Î..
  42. Tedin K, Norel F. Comparison of DeltarelA strains of Escherichia coli and Salmonella enterica serovar Typhimurium suggests a role for ppGpp in attenuation regulation of branched-chain amino acid biosynthesis. J Bacteriol. 2001;183:6184-96 pubmed
    ..Roles for ppGpp in branched-chain amino acid biosynthesis are discussed in terms of effects on the synthesis of known global regulatory proteins and current models for the control of global RNA synthesis by ppGpp. ..
  43. Rao N, Liu S, Kornberg A. Inorganic polyphosphate in Escherichia coli: the phosphate regulon and the stringent response. J Bacteriol. 1998;180:2186-93 pubmed
    ..high levels of (p)ppGpp independent of whether they are generated by RelA (active during the stringent response) or SpoT (expressed during Pi starvation)...
  44. Murray K, Bremer H. Control of spoT-dependent ppGpp synthesis and degradation in Escherichia coli. J Mol Biol. 1996;259:41-57 pubmed
    Escherichia coli has two ppGpp synthetases, PSI and PSII, encoded by the relA and spoT genes. The spoT gene also encodes a ppGpp hydrolase...
  45. Gully D, Bouveret E. A protein network for phospholipid synthesis uncovered by a variant of the tandem affinity purification method in Escherichia coli. Proteomics. 2006;6:282-93 pubmed
    ..Taken together, these results describe an integrated protein network that could be involved in the coordination of phospholipid metabolism. ..
  46. Johansson J, Balsalobre C, Wang S, Urbonaviciene J, Jin D, Sonden B, et al. Nucleoid proteins stimulate stringently controlled bacterial promoters: a link between the cAMP-CRP and the (p)ppGpp regulons in Escherichia coli. Cell. 2000;102:475-85 pubmed
    ..increased growth rate were isolated, and mapping of a suppressor mutation revealed a base pair substitution in the spoT gene. The spoT(A404E) mutant showed low ppGpp synthesizing ability...
  47. Merrikh H, Ferrazzoli A, Lovett S. Growth phase and (p)ppGpp control of IraD, a regulator of RpoS stability, in Escherichia coli. J Bacteriol. 2009;191:7436-46 pubmed publisher
    ..The expression of iraD was under the control of ppGpp. The expression of iraD required RelA and SpoT (p)ppGpp synthetase activities and was dramatically induced by a "stringent" allele of RNA polymerase, ..
  48. Wright B, Minnick M. Reversion rates in a leuB auxotroph of Escherichia coli K-12 correlate with ppGpp levels during exponential growth. Microbiology. 1997;143 ( Pt 3):847-54 pubmed
    Two isogenic strains of Escherichia coli K-12 differing only in relA, as well as two spoT transductants of the relA- strain, were examined with respect to ppGpp levels and reversion rates of a leuB- allele under nine different conditions...
  49. Heinemeyer E, Richter D. Characterization of the guanosine 5'-triphosphate 3'-diphosphate and guanosine 5'-diphosphate 3'-diphosphate degradation reaction catalyzed by a specific pyrophosphorylase from Escherichia coli. Biochemistry. 1978;17:5368-72 pubmed
    ..3'-diphosphate (ppGpp) are specifically degraded by a manganese-dependent pyrophosphorylase present in spoT+ but not in spoT- strains of Escherichia coli, indicating that the enzyme is the spoT gene product...
  50. Szalewska Pałasz A. Properties of Escherichia coli RNA polymerase from a strain devoid of the stringent response alarmone ppGpp. Acta Biochim Pol. 2008;55:317-23 pubmed
    ..Thus, it may be concluded that ppGpp present in the bacterial cell prior to purification of the RNA polymerase does not result in the alterations to the enzyme that could be permanent and affect its in vitro transcription capacity. ..
  51. An G, Justesen J, Watson R, Friesen J. Cloning the spoT gene of Escherichia coli: identification of the spoT gene product. J Bacteriol. 1979;137:1100-10 pubmed
    We have isolated five specialized transducing lambda bacteriophages (lambda dpyrE spoT) carrying the pyrE and spoT genes of Escherichia coli...
  52. Yang X, Ishiguro E. Temperature-sensitive growth and decreased thermotolerance associated with relA mutations in Escherichia coli. J Bacteriol. 2003;185:5765-71 pubmed
    ..g., relA mutants lost viability at 42 degrees C, a temperature that is normally nonlethal. The spoT gene encodes a bifunctional enzyme possessing ppGpp synthetase and ppGpp pyrophosphohydrolase activities...
  53. Ostrowski E, Woods R, Lenski R. The genetic basis of parallel and divergent phenotypic responses in evolving populations of Escherichia coli. Proc Biol Sci. 2008;275:277-84 pubmed
    ..Substitutions in the same locus clustered together phenotypically, indicating concordance between molecular and phenotypic measures of divergence. ..
  54. Flores N, Escalante A, de Anda R, Báez Viveros J, Merino E, Franco B, et al. New insights into the role of sigma factor RpoS as revealed in escherichia coli strains lacking the phosphoenolpyruvate:carbohydrate phosphotransferase system. J Mol Microbiol Biotechnol. 2008;14:176-92 pubmed
    ..The transcription level of gpp, spoT, ppa and ndk whose products are involved in ppGpp metabolism was upregulated in strain PB12 as compared to the ..
  55. Lemke J, Sanchez Vazquez P, Burgos H, Hedberg G, Ross W, Gourse R. Direct regulation of Escherichia coli ribosomal protein promoters by the transcription factors ppGpp and DksA. Proc Natl Acad Sci U S A. 2011;108:5712-7 pubmed publisher
    ..We conclude that direct control of r-protein promoters and rRNA promoters by the same signal, ppGpp/DksA, makes a major contribution to the balanced and coordinated synthesis rates of all of the ribosomal components. ..
  56. Dennis P, Ehrenberg M, Bremer H. Control of rRNA synthesis in Escherichia coli: a systems biology approach. Microbiol Mol Biol Rev. 2004;68:639-68 pubmed
    ..This control of rrn P1 promoter strength forms part of a larger feedback loop that adjusts the synthesis of ribosomes to the availability of amino acids via amino acid-dependent control of ppGpp accumulation. ..
  57. Jishage M, Kvint K, Shingler V, Nystrom T. Regulation of sigma factor competition by the alarmone ppGpp. Genes Dev. 2002;16:1260-70 pubmed
    ..Thus, the stringent response encompasses a mechanism that alters the relative competitiveness of sigma factors in accordance with cellular demands during physiological stress. ..
  58. Gully D, Moinier D, Loiseau L, Bouveret E. New partners of acyl carrier protein detected in Escherichia coli by tandem affinity purification. FEBS Lett. 2003;548:90-6 pubmed
    ..Furthermore, this study shows how the TAP method can be simply used in prokaryotes such as E. coli to identify new partners in protein-protein interactions under physiological conditions and thereby uncover novel protein functions. ..
  59. Fujita C, Maeda M, Fujii T, Iwamoto R, Ikehara K. Identification of an indispensable amino acid for ppGpp synthesis of Escherichia coli SpoT protein. Biosci Biotechnol Biochem. 2002;66:2735-8 pubmed
    ..Amino acid substitutions were introduced into a structurally flexible and highly conserved region of Escherichia coli SpoT protein. SpoT protein changed from Asp to Ala at the 293rd position did not restore cell growth of E...
  60. VanBogelen R, Neidhardt F. Ribosomes as sensors of heat and cold shock in Escherichia coli. Proc Natl Acad Sci U S A. 1990;87:5589-93 pubmed
    ..The results implicate the ribosome as a prokaryotic sensor for the heat and cold shock response networks, a role it may serve in eukaryotes as well. ..
  61. Murphy H, Cashel M. Isolation of RNA polymerase suppressors of a (p)ppGpp deficiency. Methods Enzymol. 2003;371:596-601 pubmed
  62. Metzger S, Sarubbi E, Glaser G, Cashel M. Protein sequences encoded by the relA and the spoT genes of Escherichia coli are interrelated. J Biol Chem. 1989;264:9122-5 pubmed
    relA and spoT are designations for two unlinked Escherichia coli genes whose products function in the synthesis and degradation of guanosine 3',5'-bispyrophosphate during the stringent regulatory response to amino acid deprivation...
  63. Thomas J, Rigden D, Cronan J. Acyl carrier protein phosphodiesterase (AcpH) of Escherichia coli is a non-canonical member of the HD phosphatase/phosphodiesterase family. Biochemistry. 2007;46:129-36 pubmed
    ..related to a phosphodiesterase of known structure, the hydrolyase domain of the bifunctional bacterial protein, SpoT, suggesting that AcpH is a member of the HD family of phosphatases/ phosphodiesterases despite lacking the ..
  64. Wu J, Xie J. Magic spot: (p) ppGpp. J Cell Physiol. 2009;220:297-302 pubmed publisher
    ..Therefore, more attention should be focused on the molecular mechanisms of (p) ppGpp, as it is the foundation to understanding how bacteria adapt to extreme circumstances through the stringent response. ..
  65. Magnusson L, Gummesson B, Joksimović P, Farewell A, Nystrom T. Identical, independent, and opposing roles of ppGpp and DksA in Escherichia coli. J Bacteriol. 2007;189:5193-202 pubmed
    ..In addition, ppGpp and DksA have opposing effects on adhesion. In the course of our analysis, we also discovered new features of the relaxed mutant, namely, defects in cell-cell aggregation and motility. ..
  66. Spira B, Hu X, Ferenci T. Strain variation in ppGpp concentration and RpoS levels in laboratory strains of Escherichia coli K-12. Microbiology. 2008;154:2887-95 pubmed publisher
    ..The elevated ppGpp was caused by two mutations in spoT, a gene associated with ppGpp synthesis and degradation...
  67. Haddadin F, Kurtz H, Harcum S. Serine hydroxamate and the transcriptome of high cell density recombinant Escherichia coli MG1655. Appl Biochem Biotechnol. 2009;157:124-39 pubmed publisher
    ..These results indicate that recombinant protein production and the stringent response have many overlapping responses but are far from identical. ..
  68. Harinarayanan R, Murphy H, Cashel M. Synthetic growth phenotypes of Escherichia coli lacking ppGpp and transketolase A (tktA) are due to ppGpp-mediated transcriptional regulation of tktB. Mol Microbiol. 2008;69:882-94 pubmed publisher
    ..Both routes of activation are magnified by elevating ppGpp levels with a spoT mutation (spoT-R39A) defective in hydrolase but not synthetase activity or with the stringent suppressor mutations ..
  69. Richter D. Uncharged tRNA inhibits guanosine 3',5'-bis (diphosphate) 3'-pyrophosphohydrolase [ppGppase], the spoT gene product, from Escherichia coli. Mol Gen Genet. 1980;178:325-7 pubmed
    The spot gene product from Escherichia coli, the guanosine 3',5'-bis(diphosphate) 3'-pyrophos phohydrolase [ppGppase] catalyzes the specific release of pyrophosphate from the 3'-position of guanosine 3',5'-bis(diphosphate) [ppGpp]; this ..
  70. Sarubbi E, Rudd K, Xiao H, Ikehara K, Kalman M, Cashel M. Characterization of the spoT gene of Escherichia coli. J Biol Chem. 1989;264:15074-82 pubmed
    The Escherichia coli spoT gene encodes a guanosine-3',5'-bispyrophosphate (ppGpp) 3'-pyrophosphohydrolase known to be responsible for cellular (ppGpp) degradation. The DNA sequence of the spoT region is presented...
  71. Costanzo A, Ades S. Growth phase-dependent regulation of the extracytoplasmic stress factor, sigmaE, by guanosine 3',5'-bispyrophosphate (ppGpp). J Bacteriol. 2006;188:4627-34 pubmed