Cloning and sequencing of a 36-kb region of the Bacillus subtilis genome between the gnt and iol operons

Abstract

Within the framework of an international project for the sequencing of the entire Bacillus subtilis genome, a 36-kb chromosome segment, which covers the region between the gnt and iol operons, has been cloned and sequenced. This region (36447 bp) contains 33 complete open reading frames (ORFs; genes) including the four gnt genes and one partial gene. A homology search for the products of the 33 complete ORFs revealed significant homology to known proteins in 16 of them such as tetracycline resistance protein (Clostridium perfringens), asparagine synthetase (Arabidopsis thaliana), aldehyde dehydrogenase (Pseudomonas oleovorans), 2,5-dichloro-2,5-cyclohexadiene-1,4-diol dehydrogenase (P. paucimobilis), heat shock protein HtpG (Escherichia coli), galactose-proton symporter (E. coli), auxin-induced protein (common tobacco), glucitol operon repressor (E. coli) and methylmalonate-semialdehyde dehydrogenase (P. aeruginosa). Unlike the regions we sequenced so far, this region contained two short sequence multiplications: one was a tandem sequence duplication (409 and 410 bp), and the other a triplication consisting of two highly conserved 118-bp tandem sequences preceded by a less conserved similar sequence (129 bp). The reasons for the presence of these sequence multiplications in the gnt to iol region were deduced.