Identification and characterization of vaccine targets for Brucella melitensis through in silico approaches

Abstract The present chapter provides the applicability of computational tools to identify drug targets in Brucella militensis 16M based on the genomic information. To accomplish this task, subtractive genomic approach was used and the pipeline used to identify the drug targets through subtractive genomic approach was presented in the materials and methods section. The basic principle behind the subtractive genomic approach is to identify genes with common signaling or properties in humans and the test pathogen, B. militensis. After removal of the common genes between the host and the pathogen, identification of drug targets could be possible for the unique genes in the pathogen. In brief, Brucella melitensis 16M complete genome sequence was retrieved from the National Center for Biotechnology Information (NCBI) followed by the identification of essential genes and paralogs using Data Base of Essential Gene analysis. Homologous and non-homologous genes in B. militensis 16M were identified by using the available human genome sequence. After proper removal of paralogs, the remaining essential non-homologous genes were subjected to Kyoto Encyclopedia of Genes and Genomes (KEGG) Kyoto Automatic Annotation Server (KAAS) analysis to identify unique pathways in B. melitensis 16M. The findings revealed that a total of 1139 and 117 non-homologous genes were identified in chromosome I and II, respectively. Further, 6.7% (77/1139) and 42% (49/117) unique non-homologous genes were identified in chromosomes I and II, respectively using DEG database. Finally, subtractive genomic approach revealed identification of 57 characterized and 13 (uncharacterized) hypothetical proteins in the genome of B. melitensis 16M. This information helped in understanding genes that identify putative drug targets and drug targets which is involved in 14 metabolic pathways. Thus, the present chapter describes the applicability of bioinformatic tools to identify drug targets in B. militensis 16M using subtractive genomic approach.