Colicin E7
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| + | <StructureSection load='2axc' size='450' side='right' scene='Colicin_E7/Cole7t/1' caption=''> | ||
Colicin E7 is a type of [[Colicin]], a bacteriocin made by ''E. coli'' which acts against other nearby ''E. coli'' to kill them with its [[DNase Activity]]; it digests the cell's genome in specific locations, ultimately leading to the death of the cell. | Colicin E7 is a type of [[Colicin]], a bacteriocin made by ''E. coli'' which acts against other nearby ''E. coli'' to kill them with its [[DNase Activity]]; it digests the cell's genome in specific locations, ultimately leading to the death of the cell. | ||
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==Mechanism of uptake== | ==Mechanism of uptake== | ||
| - | {{STRUCTURE_2axc | PDB=2axc | SCENE= Colicin_E7/Cole7t/1 }} | ||
The receptor binding domain of ColE7 binds to the [[BtuB]] vitamin B12 receptor on the outer membrane of the target cell. This causes the dissociation of the immunity protein from the cytotoxic domain of the colicin, allowing it to target the cell when it enters. Binding BtuB triggers the recruitment of [[OmpF]] and the TolQRAB complex, to bind to the translocation domain and translocate the colicin across the membrane. The mechanism by which this occurs has not yet been identified. This structure shows the translocation domain of ColE7. | The receptor binding domain of ColE7 binds to the [[BtuB]] vitamin B12 receptor on the outer membrane of the target cell. This causes the dissociation of the immunity protein from the cytotoxic domain of the colicin, allowing it to target the cell when it enters. Binding BtuB triggers the recruitment of [[OmpF]] and the TolQRAB complex, to bind to the translocation domain and translocate the colicin across the membrane. The mechanism by which this occurs has not yet been identified. This structure shows the translocation domain of ColE7. | ||
==Killing Activities== | ==Killing Activities== | ||
| - | {{STRUCTURE_1pt3 | PDB=1pt3 | SCENE= Colicin_E7/Cole7cmono/1 }} | ||
| - | Colicin E7 has an endonuclease domain that degrades the DNA of the targeted cell, containing an [[H-N-H motif]]. This structure shows <scene name='Colicin_E7/Cole7c/1'>this domain</scene> bound to a <scene name='Colicin_E7/Dnaoctomer/1'>DNA octamer</scene><ref> PMID: 14962381 </ref>. | ||
| - | + | <scene name='Colicin_E7/Cole7cmono/1'>Colicin E7</scene> has an endonuclease domain that degrades the DNA of the targeted cell, containing an [[H-N-H motif]]. This structure shows <scene name='Colicin_E7/Cole7c/1'>this domain</scene> bound to a <scene name='Colicin_E7/Dnaoctomer/1'>DNA octamer</scene><ref> PMID: 14962381 </ref>. | |
| + | The endonuclease domain is likely to use Zn<sup>2+</sup><ref> PMID: 11917029 </ref> in the DNA cleavage, although other literature does not support this<ref> PMID: 15190054 </ref>. For cleavage of single stranded DNA or RNA ColE7 can either use Ni<sup>2+</sup> or Co<sup>2+</sup><ref>PMID: 12162738</ref><ref>PMID: 11733993 </ref>. The bound ion binds to the second histadine residue in the HNH motif and stabilises the reaction. | ||
| + | </StructureSection> | ||
==References== | ==References== | ||
<references/> | <references/> | ||
Current revision
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References
- ↑ Hsia KC, Chak KF, Liang PH, Cheng YS, Ku WY, Yuan HS. DNA binding and degradation by the HNH protein ColE7. Structure. 2004 Feb;12(2):205-14. PMID:14962381 doi:10.1016/j.str.2004.01.004
- ↑ Ku WY, Liu YW, Hsu YC, Liao CC, Liang PH, Yuan HS, Chak KF. The zinc ion in the HNH motif of the endonuclease domain of colicin E7 is not required for DNA binding but is essential for DNA hydrolysis. Nucleic Acids Res. 2002 Apr 1;30(7):1670-8. PMID:11917029
- ↑ Mate MJ, Kleanthous C. Structure-based analysis of the metal-dependent mechanism of H-N-H endonucleases. J Biol Chem. 2004 Aug 13;279(33):34763-9. Epub 2004 Jun 8. PMID:15190054 doi:10.1074/jbc.M403719200
- ↑ Keeble AH, Hemmings AM, James R, Moore GR, Kleanthous C. Multistep binding of transition metals to the H-N-H endonuclease toxin colicin E9. Biochemistry. 2002 Aug 13;41(32):10234-44. PMID:12162738
- ↑ Pommer AJ, Cal S, Keeble AH, Walker D, Evans SJ, Kuhlmann UC, Cooper A, Connolly BA, Hemmings AM, Moore GR, James R, Kleanthous C. Mechanism and cleavage specificity of the H-N-H endonuclease colicin E9. J Mol Biol. 2001 Dec 7;314(4):735-49. PMID:11733993 doi:10.1006/jmbi.2001.5189
