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Team:Valencia/Project1
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| - | ''' | + | '''Colicin G and Colicin H''' |
| - | + | Colicins are proteins produced by some strains of Escherichia coli that are lethal for related strains of E. coli. | |
Colicins of strain CA46 (colicin G producer) and of strain CA58 (colicin H producer) should be the same, and indeed, the sensitivity patterns were nearly identical. | Colicins of strain CA46 (colicin G producer) and of strain CA58 (colicin H producer) should be the same, and indeed, the sensitivity patterns were nearly identical. | ||
Only the triple mutant receptors fepA cir fiu was completely resistant to the colicins from these strains. | Only the triple mutant receptors fepA cir fiu was completely resistant to the colicins from these strains. | ||
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(iii) colicin kills sensitive cells according to single-hit kinetics. | (iii) colicin kills sensitive cells according to single-hit kinetics. | ||
| - | (iv) colicin is not active against the producing bacteria | + | (iv) colicin is not active against the producing bacteria if there is presence of a specific antagonist protein called the '''immunity protein'''. |
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Escherichia coli microcin operon, strain CA58 (CA58 ColH) | Escherichia coli microcin operon, strain CA58 (CA58 ColH) | ||
[http://www.ncbi.nlm.nih.gov/nuccore/AJ515252] | [http://www.ncbi.nlm.nih.gov/nuccore/AJ515252] | ||
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| + | == Microcin C51 == | ||
| + | |||
| + | Microcin C51 is a nucleopeptide of 1.18 kDa molecular mass and the first described nucleopeptide antibiotic. It contains a heptapeptide with the N-terminal formylmethionine and C-terminal asparagine bound to AMP via an aliphatic chain. Microcine C51 is characterized by a broad spectrum of action. Expression in Escherichia coli is activated upon decelerated growth of cells during their transition to the stationary growth phase. | ||
Revision as of 07:04, 20 September 2011
Colicin G and Colicin H
Colicins are proteins produced by some strains of Escherichia coli that are lethal for related strains of E. coli. Colicins of strain CA46 (colicin G producer) and of strain CA58 (colicin H producer) should be the same, and indeed, the sensitivity patterns were nearly identical. Only the triple mutant receptors fepA cir fiu was completely resistant to the colicins from these strains.
(i) the production of colicin by colicinogenic E. coli cells is induced by SOS agents, as is seen with lysogenic phages, and is lethal for producing cells.
(ii) the produced colicin is released into the medium late after synthesis (later shown not to be the case for all colicins).
(iii) colicin kills sensitive cells according to single-hit kinetics.
(iv) colicin is not active against the producing bacteria if there is presence of a specific antagonist protein called the immunity protein.
All colicins are organized into three domains, each corresponding to one step of colicin action:
o The N-terminal domain is involved in translocation through the membrane.
o The central domain is involved in binding to the receptor.
o The C-terminal domain contains the active part.
Cascales E. et al. Colicin Biology. Microbiol Mol Biol Rev. 2007 March; 71(1): 158–229.
The sequence of the colicin G and colicin H determinants have been deposited under the accession numbers AJ515251 and AJ515252, respectively, in the EMBL/GenBank database.
Escherichia coli microcin operon, strain CA46 (CA46 ColG) [http://www.ncbi.nlm.nih.gov/nuccore/AJ515251]
Escherichia coli microcin operon, strain CA58 (CA58 ColH) [http://www.ncbi.nlm.nih.gov/nuccore/AJ515252]
Microcin C51
Microcin C51 is a nucleopeptide of 1.18 kDa molecular mass and the first described nucleopeptide antibiotic. It contains a heptapeptide with the N-terminal formylmethionine and C-terminal asparagine bound to AMP via an aliphatic chain. Microcine C51 is characterized by a broad spectrum of action. Expression in Escherichia coli is activated upon decelerated growth of cells during their transition to the stationary growth phase.
