Characterization of Conserved Hypothetical Proteins from Proteome of Xanthomonas citri subsp. citri, with Ethylene Induction Activity on Arabidopsis thaliana

In previous work we showed that a purified extract of the proteome of bacterium Xcc that was able to induce ethylene production on Arabidopsis. Among the approximately 60 different putative proteins in the extract, eight were identified as conserved hypothetical proteins. The aim of this study is to use different bioinformatics tools to characterize these proteins. All of the investigated proteins ranged in size between 17.11 and 43.84 kilo Daltons with Protein NP_640497.1 being the largest. Calculated isoelectric points (pI) for proteins varied between 5.34 and 9.5. The type of protein families and domains of proteins was determined by conserved domain database (CDD-Blast) and Interpro. Among the investigated proteins, proteins NP_640912.1 had a HTH domain (Helix-turn-Helix); the central part of protein NP_640497 contained an Enoyl reductase domain; protein NP_641576.1 contained two calcium binding motifs (EF-hand, calcium binding motif); and protein NP_643454.1 contained a 4-hydroxybenzoyl-CoA thiesterase motif from the Hot dog superfamily. COACH server was used for predication of ligand binding sites of proteins and their three dimensional structure was modeled by Phyre 2 server. Results from this research can be used for better understanding of Xcc and also identification of proteins with elicitor activity from this bacterium.