INFECTIOUS AGENTS 

However, in the C. diphtheriae genome, the high Guanine-cytosine content is not constant throughout the whole genome as there have been findings that show that in the region around the terminus there is a significantly low high Guanine-cytosine content, and this reflects on its genetic diversity (Cerdeno-Tarraga, 2003).  This is the cause of the 102 strains of C. diphtheriae and change in genome (Titov et al , 2003).

C. Diphtheriae toxins have 3 structural domains and each of them have a different biological function implicated in the intoxication of cells. The functions vary from cell surface binding, internalisation into endosomes and then crossing the endosome membrane to go into the cytosol and blocking cellular protein synthesis (Gillet et al, 2015).  Moreover , C.diphtheriae toxins have a crystal structure which consists of 1,046 amino acid residues , including 2 bound adenylyl 3′‐5′ uridine 3′ monophosphate molecules and 396 water molecules (Bennett and Eisenberg, 1994).

In the cell wall of C. diphtheriae, it contains an arabinogalactan polymer that anchors an outer lipid‐rich domain to the murein sacculus of the cell. Alpha-alkyl, beta-hydroxy fatty acids and corynomycolic acids are produced through a Claisen-like condensation reaction between two fatty acyl chains. Moreover, there are pilli found on the exterior and sortase-like proteins are produced to help with anchoring of the pilli and polymerising them (Cerdeno-Tarraga, 2003) . As shown in figure 1, SpaA-type pilus is composed of a major pilin subunit SpaA and this is important for the formation of the pilus structure. pilin motif and the sorting signal are  both necessary and sufficient to promote pilus polymerization by a process requiring the function of a pilus-specific sortase (Mandlik et al , 2010).