Changes

*RTX toxins:

*RTX toxins:

**'Repeat in ToXin' - named because there are several peptide repeats within the molecules

**'Repeat in ToXin' - named because there are several peptide repeats within the molecules

**Produced by various Gram-negative bacteria, including  

**Produced by various Gram-negative bacteria, including [[Escherichia coli|''E. coli'']]

**Possess four contiguous genes, C, A, B and D

**Possess four contiguous genes, C, A, B and D

**A is the structural gene; B and D are required for secretion; C is required for post-translational activation of the gene product of A to produce a functional product

**A is the structural gene; B and D are required for secretion; C is required for post-translational activation of the gene product of A to produce a functional product