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Gene Review

yjjX  -  non-canonical purine NTP phosphatase,...

Escherichia coli str. K-12 substr. MG1655

Synonyms: ECK4386, JW5801
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Disease relevance of yjjX


High impact information on yjjX

  • Helicases are motor proteins that couple the hydrolysis of nucleoside triphosphate (NTPase) to nucleic acid unwinding [1].
  • Limited tryptic digestion of Escherichia coli transcription termination factor rho [an RNA-dependent nucleoside triphosphatase (NTPase)] yields predominantly two fragments (f1 and f2) when the protein is bound to both poly(C) and ATP [6].
  • We suggest that rho NTPase is regulated by RNA polymerase (EC so that during transcription elongation the RNA polymerase competes successfully with rho for substrates and inhibits rho NTPase with product pyrophosphate [7].
  • The NTPase Walker A active site of the inner membrane protein VirB4 is required for virulence, but an active site VirB4 variant stabilized VirB3 and VirB8 and enabled T-pilus formation [8].
  • Both NTPase and pyrophosphatase activities were enhanced at higher temperatures and blocked by the alpha,beta-methyleneadenosine triphosphate, which cannot be hydrolyzed by Tm-MazG [9].

Chemical compound and disease context of yjjX

  • Biochemical studies indicate that the M. luteus protein is very similar to E. coli Rho in terms of its RNA-dependent NTPase activity and its sensitivity to the Rho-specific inhibitor bicyclomycin [10].
  • The hepatitis C virus nonstructural 3 protein (NS3) possesses a serine protease activity in the N-terminal one-third, whereas RNA-stimulated NTPase and helicase activities reside in the C-terminal portion [11].
  • The nucleoside triphosphate hydrolase (NTPase) isoforms termed, NTPase-I and NTPase-II of Toxoplasma gondii, were expressed in Escherichia coli as inclusion bodies and purified under denaturing condition [12].

Biological context of yjjX

  • The helicase and NTPase activities of full-length NS3 have been demonstrated and we have characterized the effects of amino acid substitutions on conserved motifs of NS3 helicase [13].
  • Southern blotting showed a gene copy number of between one and five, and the possibility that ntp is tandemly repeated over a large length of DNA [14].
  • The non-structural protein 3 (NS3) of hepatitis C virus (HCV) possesses three activities which are likely to be essential for virus replication; a serine protease located in the N terminus and helicase and NTPase activities located in the C terminus [13].
  • Based on comparative analysis with other related proteins of the Lactobacillus and Lactococcus phages as well as the Escherichia coli phages (such as lambda), functions were putatively assigned to several phi g1e ORFs: cng and cpg (encoding for repressors), hel (helicase), ntp (NTPase), and several ORFs (e.g., minor capsid proteins) [15].
  • 5. The substrate specificity was broad and a nonspecific Mg2+-independent ribonucleoside-triphosphatase (NTPase) activity was expressed together with thiamin-triphosphatase activity [16].

Anatomical context of yjjX

  • This may be a particular example of a more general class of pattern forming mechanisms, based on protein oligomerization upon a template (membranes, DNA a.o.) with resulting enhanced NTPase function in the oligomer state, which may bring the oligomer into an unstable internal state [17].

Associations of yjjX with chemical compounds

  • Further, RNA polymerase pausing may result in reduced pyrophosphate and increased NTP concentrations, allowing rho NTPase to function [7].
  • As is true for synthetic polynucleotides known to activate the rho NTPase, the trp t' region has few G residues [18].
  • Wild-type rho must bind single-stranded polynucleotides to activate its nucleotide triphosphatase (NTPase) activity, and either poly(C), or poly(dC) plus oligo(C), will suffice [19].
  • N-terminal deletion analysis to express a truncated form of Rho (Rho 72, 72 kDa) indicated that the first 42 residues of Rho 77 were not essential for RNA-dependent NTPase activity and were not the targets of inhibition by heparin or bicyclomycin [5].
  • Our results reveal that the functional domains required for serine protease and RNA-stimulated NTPase activities map within the region between amino acid residues 160 and 180 of NS3 protein and that a novel motif, the cluster of basic residues 184RKRK, plays an important role for the RNA-stimulated NTPase activity [20].

Other interactions of yjjX

  • In the absence of any other viral factors, the fusion product had NTPase, RNA binding and RNA helicase activities [21].

Analytical, diagnostic and therapeutic context of yjjX


  1. Structure and function of hexameric helicases. Patel, S.S., Picha, K.M. Annu. Rev. Biochem. (2000) [Pubmed]
  2. A steady-state and pre-steady-state kinetic analysis of the NTPase activity associated with the hepatitis C virus NS3 helicase domain. Preugschat, F., Averett, D.R., Clarke, B.E., Porter, D.J. J. Biol. Chem. (1996) [Pubmed]
  3. Poliovirus protein 2C has ATPase and GTPase activities. Rodríguez, P.L., Carrasco, L. J. Biol. Chem. (1993) [Pubmed]
  4. The severe acute respiratory syndrome (SARS) coronavirus NTPase/helicase belongs to a distinct class of 5' to 3' viral helicases. Tanner, J.A., Watt, R.M., Chai, Y.B., Lu, L.Y., Lin, M.C., Peiris, J.S., Poon, L.L., Kung, H.F., Huang, J.D. J. Biol. Chem. (2003) [Pubmed]
  5. Isolation and sequencing of the rho gene from Streptomyces lividans ZX7 and characterization of the RNA-dependent NTPase activity of the overexpressed protein. Ingham, C.J., Hunter, I.S., Smith, M.C. J. Biol. Chem. (1996) [Pubmed]
  6. Escherichia coli transcription termination factor rho has a two-domain structure in its activated form. Bear, D.G., Andrews, C.L., Singer, J.D., Morgan, W.D., Grant, R.A., von Hippel, P.H., Platt, T. Proc. Natl. Acad. Sci. U.S.A. (1985) [Pubmed]
  7. Pyrophosphate inhibition of rho ATPase: a mechanism of coupling to RNA polymerase activity. Kent, R.B., Guterman, S.K. Proc. Natl. Acad. Sci. U.S.A. (1982) [Pubmed]
  8. Identification of the VirB4-VirB8-VirB5-VirB2 pilus assembly sequence of type IV secretion systems. Yuan, Q., Carle, A., Gao, C., Sivanesan, D., Aly, K.A., Höppner, C., Krall, L., Domke, N., Baron, C. J. Biol. Chem. (2005) [Pubmed]
  9. Thermotoga maritima MazG protein has both nucleoside triphosphate pyrophosphohydrolase and pyrophosphatase activities. Zhang, J., Zhang, Y., Inouye, M. J. Biol. Chem. (2003) [Pubmed]
  10. Characterization of an unusual Rho factor from the high G + C gram-positive bacterium Micrococcus luteus. Nowatzke, W.L., Richardson, J.P. J. Biol. Chem. (1996) [Pubmed]
  11. Modulation of hepatitis C virus NS3 protease and helicase activities through the interaction with NS4A. Gallinari, P., Paolini, C., Brennan, D., Nardi, C., Steinkühler, C., De Francesco, R. Biochemistry (1999) [Pubmed]
  12. Evaluation of serodiagnosis of toxoplasmosis by using the recombinant nucleoside triphosphate hydrolase isoforms expressed in Escherichia coli. Nakajima-Nakano, K., Makioka, A., Yamashita, N., Matsuo, N., Asai, T. Parasitol. Int. (2000) [Pubmed]
  13. Characterization and mutational analysis of the helicase and NTPase activities of hepatitis C virus full-length NS3 protein. Wardell, A.D., Errington, W., Ciaramella, G., Merson, J., McGarvey, M.J. J. Gen. Virol. (1999) [Pubmed]
  14. Cloning, expression and nucleotide sequence of the gene fragment encoding an antigenic portion of the nucleoside triphosphate hydrolase of Toxoplasma gondii. Johnson, A.M., Illana, S., McDonald, P.J., Asai, T. Gene (1989) [Pubmed]
  15. Genome structure of the Lactobacillus temperate phage phi g1e: the whole genome sequence and the putative promoter/repressor system. Kodaira, K.I., Oki, M., Kakikawa, M., Watanabe, N., Hirakawa, M., Yamada, K., Taketo, A. Gene (1997) [Pubmed]
  16. Nucleoside-triphosphatase and hydrolysis of thiamin triphosphate in Escherichia coli. Nishimune, T., Ito, S., Abe, M., Kimoto, M., Hayashi, R. Biochim. Biophys. Acta (1987) [Pubmed]
  17. A mechanism for ParB-dependent waves of ParA, a protein related to DNA segregation during cell division in prokaryotes. Hunding, A., Ebersbach, G., Gerdes, K. J. Mol. Biol. (2003) [Pubmed]
  18. Rho-dependent termination and concomitant NTPase activity requires a specific, intact RNA region. Sharp, J.A., Platt, T. J. Biol. Chem. (1984) [Pubmed]
  19. The rho-115 mutation in transcription termination factor rho affects its primary polynucleotide binding site. Sharp, J.A., Guterman, S.K., Platt, T. J. Biol. Chem. (1986) [Pubmed]
  20. The serine protease and RNA-stimulated nucleoside triphosphatase and RNA helicase functional domains of dengue virus type 2 NS3 converge within a region of 20 amino acids. Li, H., Clum, S., You, S., Ebner, K.E., Padmanabhan, R. J. Virol. (1999) [Pubmed]
  21. RNA helicase activity of the plum pox potyvirus CI protein expressed in Escherichia coli. Mapping of an RNA binding domain. Fernández, A., Laín, S., García, J.A. Nucleic Acids Res. (1995) [Pubmed]
  22. Recombinant dengue virus type 1 NS3 protein exhibits specific viral RNA binding and NTPase activity regulated by the NS5 protein. Cui, T., Sugrue, R.J., Xu, Q., Lee, A.K., Chan, Y.C., Fu, J. Virology (1998) [Pubmed]
  23. ATPase and GTPase activities copurifying with GTP-binding proteins in E. coli. Sayed, A., Matsuyama, S., Inoue, K., Alsina, J., Cai, F., Chen, J., Inouye, M. J. Mol. Microbiol. Biotechnol. (2000) [Pubmed]
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