Colicin A: Difference between revisions

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Colicin A is a type of [[Colicin]], a bacteriocin made by E. Coli which acts against other nearby E. Coli to kill them by forming a pore in the membrane, leading to depolarisation of the membrane which kills the cell.

==Synthesis ~~and release~~==

==Synthesis==

Colicin A is synthesised through a single operon, containing the colicin A lysis protein encoding gene, Cal. The Cal gene is also involved in the expression of the colicin A operon - without the cal gene the amount of colicin A produced decreases<ref> PMID: 9245818 </ref>. The cal gene product is likely to be an activator of colicin A expression, including its own expression. A separate, unidentified, product (which may be a heat-shock protein) could also be involved, and complement the cal gene product<ref> PMID: 9245818 </ref>.

Colicin A is synthesised through a single operon, containing the colicin A lysis protein encoding gene, Cal. The Cal gene is also involved in the expression of the colicin A operon - without the cal gene the amount of colicin A produced decreases<ref> PMID: 9245818 </ref>. The cal gene product is likely to be an activator of colicin A expression, including its own expression. The N terminal region of the cal gene product is particularly involved in the regulation of col A synthesis. A separate, unidentified, product (which may be a heat-shock protein) could also be involved, and complement the cal gene product<ref> PMID: 9245818 </ref>.

The expression of the col A operon provokes a shut-off of chromosomal protein expression, which is due to the expression of the lysis gene. This shut-off gives the col A production a priority over other cellular proteins in their synthesis.

Synthesis of col A starts immediately after induction. At lower temperatures, like 30'c, there is a lag phase to this synthesis, which does not end in null ''cal'' mutants. At 37-42'c the lag is very short, and a large amount of col A is produced very rapidly. The signal to speed up synthesis from the lag phase involves the ''cal'' gene product, alongside the other unidentified gene product at normal and high temperatures<ref> PMID: 9245818</ref>.

''Cal'' has a self-regulatory role in the expression of both itself and the col A gene, which may be common to all colicin lysis proteins.

==Release==

==Mechanism of uptake==

Colicin A: Difference between revisions

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@@ Line 1: / Line 1: @@
 Colicin A is a type of [[Colicin]], a bacteriocin made by <i>E. Coli</i> which acts against other nearby <i>E. Coli</i> to kill them by forming a pore in the membrane, leading to depolarisation of the membrane which kills the cell.
-==Synthesis and release==
+==Synthesis==
-Colicin A is synthesised through a single operon, containing the colicin A lysis protein encoding gene, <i>Cal</i>. The <i>Cal</i> gene is also involved in the expression of the colicin A operon - without the <i>cal</i> gene the amount of colicin A produced decreases<ref> PMID: 9245818 </ref>. The <i>cal</i> gene product is likely to be an activator of colicin A expression, including its own expression. A separate, unidentified, product (which may be a heat-shock protein) could also be involved, and complement the <i>cal</i> gene product<ref> PMID: 9245818 </ref>.
+Colicin A is synthesised through a single operon, containing the colicin A lysis protein encoding gene, <i>Cal</i>. The <i>Cal</i> gene is also involved in the expression of the colicin A operon - without the <i>cal</i> gene the amount of colicin A produced decreases<ref> PMID: 9245818 </ref>. The <i>cal</i> gene product is likely to be an activator of colicin A expression, including its own expression. The N terminal region of the <i>cal</i> gene product is particularly involved in the regulation of col A synthesis. A separate, unidentified, product (which may be a heat-shock protein) could also be involved, and complement the <i>cal</i> gene product<ref> PMID: 9245818 </ref>.
 The expression of the col A operon provokes a shut-off of chromosomal protein expression, which is due to the expression of the lysis gene. This shut-off gives the col A production a priority over other cellular proteins in their synthesis.
+Synthesis of col A starts immediately after induction. At lower temperatures, like 30'c, there is a lag phase to this synthesis, which does not end in null ''cal'' mutants. At 37-42'c the lag is very short, and a large amount of col A is produced very rapidly. The signal to speed up synthesis from the lag phase involves the ''cal'' gene product, alongside the other unidentified gene product at normal and high temperatures<ref> PMID: 9245818</ref>.
+''Cal'' has a self-regulatory role in the expression of both itself and the col A gene, which may be common to all colicin lysis proteins.
+==Release==
 ==Mechanism of uptake==