Skip to main content
NCBI home page
Journal of Bacteriology logoLink to Journal of Bacteriology
. 1996 Jun;178(12):3544–3549. doi: 10.1128/jb.178.12.3544-3549.1996

The cryptic general secretory pathway (gsp) operon of Escherichia coli K-12 encodes functional proteins.

O Francetic 1, A P Pugsley 1
PMCID: PMC178124  PMID: 8655552

Abstract

Systematic sequencing of the Escherichia coli K-12 chromosome (GenBank entry U18997) has revealed the presence of an apparently complete operon of genes (the gspC-0 operon) similar to genes coding for components of the main terminal branch of the general secretory pathway (e.g., the Klebsiella oxytoca pulC-0 pullulanase secretion operon) and to related genes required for type IV pilus biogenesis. For example, the last gene in the gsp operon, gspO (formerly hopD), encodes a protein which is similar to several type IV prepilin peptidases. Expression of gspO from lacZp promotes cleavage of two known prepilin peptidase substrates in E. coli K-12: Neisseria gonorrhoeae type IV prepilin and K. oxytoca prePulG protein. gspO also complements a mutation in the corresponding gene (pulO) of the pullulanase secretion operon when it is expressed from lacZp. Another gene in the gsp operon, gspG (formerly hopG), encodes a protein similar to prePulG, a component of the pullulanase secretion pathway. Expression of gspG from lacZp leads to production of a protein which (i) is recognized by PulG-specific antiserum (and by antiserum against the Pseudomonas aeruginosa PulG homolog XcpG [formerly XcpT]), (ii) is processed in cells expressing gspO, and (iii) restores secretion in cells carrying a pulG mutation. The chromosomal copies of gspG and gspO are apparently not expressed, probably because of very weak transcription from the upstream region, as measured by using a chromosomal gspC-lacZ operon fusion. Thus, the gsp operon of E. coli K-12 includes at least two functional genes which, together with the rest of the operon, are probably not expressed under laboratory conditions.

Full Text

The Full Text of this article is available as a PDF (371.6 KB).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Andrews S. C., Harrison P. M., Guest J. R. Cloning, sequencing, and mapping of the bacterioferritin gene (bfr) of Escherichia coli K-12. J Bacteriol. 1989 Jul;171(7):3940–3947. doi: 10.1128/jb.171.7.3940-3947.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Condemine G., Dorel C., Hugouvieux-Cotte-Pattat N., Robert-Baudouy J. Some of the out genes involved in the secretion of pectate lyases in Erwinia chrysanthemi are regulated by kdgR. Mol Microbiol. 1992 Nov;6(21):3199–3211. doi: 10.1111/j.1365-2958.1992.tb01775.x. [DOI] [PubMed] [Google Scholar]
  3. D'Enfert C., Pugsley A. P. Klebsiella pneumoniae pulS gene encodes an outer membrane lipoprotein required for pullulanase secretion. J Bacteriol. 1989 Jul;171(7):3673–3679. doi: 10.1128/jb.171.7.3673-3679.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Dupuy B., Pugsley A. P. Type IV prepilin peptidase gene of Neisseria gonorrhoeae MS11: presence of a related gene in other piliated and nonpiliated Neisseria strains. J Bacteriol. 1994 Mar;176(5):1323–1331. doi: 10.1128/jb.176.5.1323-1331.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Hardie K. R., Lory S., Pugsley A. P. Insertion of an outer membrane protein in Escherichia coli requires a chaperone-like protein. EMBO J. 1996 Mar 1;15(5):978–988. [PMC free article] [PubMed] [Google Scholar]
  6. Howard S. P., Critch J., Bedi A. Isolation and analysis of eight exe genes and their involvement in extracellular protein secretion and outer membrane assembly in Aeromonas hydrophila. J Bacteriol. 1993 Oct;175(20):6695–6703. doi: 10.1128/jb.175.20.6695-6703.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Jahagirdar R., Howard S. P. Isolation and characterization of a second exe operon required for extracellular protein secretion in Aeromonas hydrophila. J Bacteriol. 1994 Nov;176(22):6819–6826. doi: 10.1128/jb.176.22.6819-6826.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Jiang B., Howard S. P. The Aeromonas hydrophila exeE gene, required both for protein secretion and normal outer membrane biogenesis, is a member of a general secretion pathway. Mol Microbiol. 1992 May;6(10):1351–1361. doi: 10.1111/j.1365-2958.1992.tb00856.x. [DOI] [PubMed] [Google Scholar]
  9. Lauer P., Albertson N. H., Koomey M. Conservation of genes encoding components of a type IV pilus assembly/two-step protein export pathway in Neisseria gonorrhoeae. Mol Microbiol. 1993 Apr;8(2):357–368. doi: 10.1111/j.1365-2958.1993.tb01579.x. [DOI] [PubMed] [Google Scholar]
  10. Michaelis S., Chapon C., D'Enfert C., Pugsley A. P., Schwartz M. Characterization and expression of the structural gene for pullulanase, a maltose-inducible secreted protein of Klebsiella pneumoniae. J Bacteriol. 1985 Nov;164(2):633–638. doi: 10.1128/jb.164.2.633-638.1985. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Nunn D. N., Lory S. Components of the protein-excretion apparatus of Pseudomonas aeruginosa are processed by the type IV prepilin peptidase. Proc Natl Acad Sci U S A. 1992 Jan 1;89(1):47–51. doi: 10.1073/pnas.89.1.47. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Nunn D. N., Lory S. Product of the Pseudomonas aeruginosa gene pilD is a prepilin leader peptidase. Proc Natl Acad Sci U S A. 1991 Apr 15;88(8):3281–3285. doi: 10.1073/pnas.88.8.3281. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Pugsley A. P., Dupuy B. An enzyme with type IV prepilin peptidase activity is required to process components of the general extracellular protein secretion pathway of Klebsiella oxytoca. Mol Microbiol. 1992 Mar;6(6):751–760. doi: 10.1111/j.1365-2958.1992.tb01525.x. [DOI] [PubMed] [Google Scholar]
  14. Pugsley A. P., Possot O. The general secretory pathway of Klebsiella oxytoca: no evidence for relocalization or assembly of pilin-like PulG protein into a multiprotein complex. Mol Microbiol. 1993 Nov;10(3):665–674. doi: 10.1111/j.1365-2958.1993.tb00938.x. [DOI] [PubMed] [Google Scholar]
  15. Pugsley A. P. Processing and methylation of PuIG, a pilin-like component of the general secretory pathway of Klebsiella oxytoca. Mol Microbiol. 1993 Jul;9(2):295–308. doi: 10.1111/j.1365-2958.1993.tb01691.x. [DOI] [PubMed] [Google Scholar]
  16. Pugsley A. P., Reyss I. Five genes at the 3' end of the Klebsiella pneumoniae pulC operon are required for pullulanase secretion. Mol Microbiol. 1990 Mar;4(3):365–379. doi: 10.1111/j.1365-2958.1990.tb00604.x. [DOI] [PubMed] [Google Scholar]
  17. Pugsley A. P. The complete general secretory pathway in gram-negative bacteria. Microbiol Rev. 1993 Mar;57(1):50–108. doi: 10.1128/mr.57.1.50-108.1993. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Richet E., Raibaud O. Supercoiling is essential for the formation and stability of the initiation complex at the divergent malEp and malKp promoters. J Mol Biol. 1991 Apr 5;218(3):529–542. doi: 10.1016/0022-2836(91)90699-7. [DOI] [PubMed] [Google Scholar]
  19. Simons R. W., Houman F., Kleckner N. Improved single and multicopy lac-based cloning vectors for protein and operon fusions. Gene. 1987;53(1):85–96. doi: 10.1016/0378-1119(87)90095-3. [DOI] [PubMed] [Google Scholar]
  20. Stojiljkovic I., Schönherr R., Kusters J. G. Identification of the hopG gene, a component of Escherichia coli K-12 type II export system, and its conservation among different pathogenic Escherichia coli and Shigella isolates. J Bacteriol. 1995 Apr;177(7):1892–1895. doi: 10.1128/jb.177.7.1892-1895.1995. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Takeshita S., Sato M., Toba M., Masahashi W., Hashimoto-Gotoh T. High-copy-number and low-copy-number plasmid vectors for lacZ alpha-complementation and chloramphenicol- or kanamycin-resistance selection. Gene. 1987;61(1):63–74. doi: 10.1016/0378-1119(87)90365-9. [DOI] [PubMed] [Google Scholar]
  22. Whitchurch C. B., Mattick J. S. Escherichia coli contains a set of genes homologous to those involved in protein secretion, DNA uptake and the assembly of type-4 fimbriae in other bacteria. Gene. 1994 Dec 2;150(1):9–15. doi: 10.1016/0378-1119(94)90851-6. [DOI] [PubMed] [Google Scholar]
  23. d'Enfert C., Reyss I., Wandersman C., Pugsley A. P. Protein secretion by gram-negative bacteria. Characterization of two membrane proteins required for pullulanase secretion by Escherichia coli K-12. J Biol Chem. 1989 Oct 15;264(29):17462–17468. [PubMed] [Google Scholar]
  24. d'Enfert C., Ryter A., Pugsley A. P. Cloning and expression in Escherichia coli of the Klebsiella pneumoniae genes for production, surface localization and secretion of the lipoprotein pullulanase. EMBO J. 1987 Nov;6(11):3531–3538. doi: 10.1002/j.1460-2075.1987.tb02679.x. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Journal of Bacteriology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES