Optimization and Efficient Purification in Production of Brucella melitensis Recombinant HSP and TF Proteins With Low Endotoxin Contents

Abstract

Background: The development of an effective subunit vaccine against brucellosis is a research area of intense. But optimization of recombinant proteins production in Escherichia coli and content of endotoxins associated with final recombinant proteins are very important. Objectives: In the present study, expression and purification of Brucella melitensis rHSP and rTF were optimized to reduce endotoxin contaminants. Materials and Methods: pDEST-tf and pDEST-hsp were transformed into E. coli BL21 (DE3), and then B. melitensis recombinant HSPA and TF proteins were overexpressed. Purification of these proteins was optimized to remove most of endotoxin contaminants from the end product using 0.1% Triton X-114 in washing buffers. Results: An endotoxin reduction of less than 0.05 EUmg/1 was achieved with protein recovery close to an 80% yield. Conclusions: As this new protocol requires only one step to simultaneously purify tagged proteins and eliminate endotoxins, it represents a substantial advantage in time, effort, and expense.