Bacillus anthracis spores, which cause anthrax. They are enelosed by an exosporium. Bacillus collagenlike protein of anthracis (BelA) is a glycoprotein, large proportion on Bacillus anthracis spore coat. They form the hair-like nap filaments on the surface of spores that play an important role in enhancing heat resistance, resistance to protease, adhesion and strong immune response of spores to the host cell. The BelA protein has three regions: region ends of the N (NTD- terminal domain)
Collagen like region (CLR- Collagen like repeat) contains the characteristic repeat
and the ends of the C (CTD- terminal domain) is the protease- resistant variety, it also has stable structure. In this study, a gene of 402 bp encoding CTD region of BelA protein has been eloned and expressed in E. coli BL21 under the fusion form with thioredoxin. The recombinant protein Trx-CTD of 34 kDa was synthesized in the soluble traction when the recombinant strain was cultivated in the inducted condition at both 28 and 37°C. the authors showed that the increase ofIPTG concentration trom 50 to 150uM enhanced amount of Trx-CTD and the recombinant protein was stable when increase IPTG over 150uM. The recombinant protein reacts specifically with polyelonal antibody against Bacillus anthracis spores antigen in Wesnt blot assay and was successfully purified by His-tag affinity chromatography. The purified recombinant protein concentration was 0,336 mg/ml.