Manohar L. Chowdary, Safdar J. , Munish K. Ahuja, Narayana K. shiva, Pankaj Gupta, Abani K. Bhushan, Ghan Shyam Khatri
A hypothetical open reading frame from Bacillus subtilis genome yjbI (NCBI genome database accession number A69844) having homology to many globin and globin-like proteins from different microbial genomes, was selectively amplified from the chromosomal DNA of B.subtilis strain 168. Th gene was cloned and over-expressed in Escherichia coli under the transcriptional control of tandem lambda PL and PR promoters, and the protein was purified to homogeneity. The single-chain monomeric hemoglobin-like protein is stable to the extent of 5.45 kcal/mol at 25 degrees C, binds carbon monoxide and shows optical spectra characteristic of homoproteins. The protein also exhibits peroxidase-like activity. The activity is enhanced in the presence of urea and guanidine hydrochloride, more so in the presence of the latter. Presumably, only a small portion of the protein is involved in peroxide activity, which is exposed with increasing concentration of the denaturants.