PROSITE documentation PDOC00481Hok/gef family cell toxic proteins signature
In Gram-negative bacteria there is a family of very small proteins which, when overexpressed, kill the cells from the inside by interfering with a vital function in the cell membrane [1]. The proteins known to belong to this family are:
- Escherichia coli chromosomal protein gef.
- Escherichia coli chromosomal protein relF.
- Plasmid F protein flmA.
- Plasmid F protein srnB.
- Plasmid R1 protein hok.
- Plasmids R16 and R483 protein pndA.
- Escherichia coli hypothetical protein ybdY.
- Escherichia coli hypothetical protein ydcB.
- Escherichia coli hypothetical protein yiaZ [3].
These proteins consist of 49 to 68 amino acids. Their N-terminal section is hydrophobic and seems [3] to form a membrane-spanning region, while the C-terminal part is located in the periplasm and contains the toxic domain. Two cysteines are conserved, one in the N-terminal part and the other in the C-terminal part; in the gef protein, this second cysteine has been shown [3] to be involved in the formation of a disulfide bond between two monomers.
As a signature pattern we selected the region that contains the end of the membrane-spanning region and ends with the second cysteine.
Last update:July 1998 / Pattern and text revised.
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PROSITE method (with tools and information) covered by this documentation:
| 1 | Authors | Gerdes K. Poulsen L.K. Thisted T. Nielsen A.K. Martinussen J. Andreasen P.H. |
| Title | The hok killer gene family in gram-negative bacteria. | |
| Source | New Biol. 2:946-956(1990). | |
| PubMed ID | 2101633 |
| 2 | Authors | Borodovsky M. Koonin E.V. Rudd K.E. |
| Title | New genes in old sequence: a strategy for finding genes in the bacterial genome. | |
| Source | Trends Biochem. Sci. 19:309-313(1994). | |
| PubMed ID | 7940673 |
| 3 | Authors | Poulsen L.K. Refn A. Molin S. Andersson P. |
| Title | Topographic analysis of the toxic Gef protein from Escherichia coli. | |
| Source | Mol. Microbiol. 5:1627-1637(1991). | |
| PubMed ID | 1943700 |
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