Relative Analysis of Codon Usage and Nucleotide Bias between Anthrax Toxin Genes Subsist Inpxo1 Plasmid of Bacillus Anthracis

Abstract

Anthrax is an ancient and acuteillness that affects alarge quantity of animal species and is caused by a bacterium Bacillus anthracis, which is a rod-shaped, gram-positive and spore-forming bacterium. Virulent forms of B.anthracishas two large pathogenicity related plasmids pXO1 and pXO2. pXO1 has the different anthrax toxin genes cya, lef, and pagA where as pXO2 has the genes accountable for capsule synthesis and degradation, capA, capB, capC, and capD.  B. anthracis express its pathogenic activity mostly over the capsule and the manufacture of a toxic compound involving three proteins known as edema factor (EF), lethal factor (LF) and protective antigen (PA). These two enormous plasmids of B.anthracisare crucial for full pathogenicity, exclusion of either of the plasmids extremely weakens the malignity of B. anthracis. In the current study we conducted the relative analysis of the codon usage and nucleotide bias of virulent genes subsist in pXO1 plasmid of B.anthracis. Codon usage bias not only plays a substantial role at the extent of gene expression, but also supports to improve the efficacy and accurateness of translation. Codon usage pattern analysis of B.anthracisgenome is essential for understanding the evolutionary characteristicsin the different species. To examine the codon usage arrangement of theB.anthracisgenome, Nucleotide sequences of the virulent genes viz cya, lef and pag were collected from National Center for Biotechnology Information (NCBI). The correlations between GC3s, whole GC content, Effective No. of Codons (ENC), Codon Adaptation Index (CAI), Codon Bias Index (CBI), Frequency of Optimal Codons (FOP), General average hydropathicity (Gravy) and Aromaticity (Aroma), of the selected genes were determined. The ENC-plot i.e., ENc values vs GC3s, Pr2 plot i.e., relationship between A3 / (A3 +T3) and G3 / (G3 +C3), Neutrality plot i.e., GC12 versus GC3s, and the RSCU of the genes, all shows codon usage bias existence in all the virulent genes subsists in pXO1 plasmid of B.anthracis genome. These results expresses the codon usage bias existing in the pXO1 plasmid’s virulent genes of B.anthracis genome could be utilized for further exploration on their evolutionary analysis as in design of primers, design of transgenes, determine of origin of species as well as prediction of gene expression level and gene function.