THE ORGANIZATION OF THE BACILLUS-SUBTILIS 168 CHROMOSOME REGION BETWEEN THE SPOVA AND SERA GENETIC-LOCI, BASED ON SEQUENCE DATA

Three different lambda phage clones with overlapping inserts of Bacill us subtilis DNA, which cover the region from spollAA to serA, have bee n isolated. The nucleotide sequence of their inserts, starting after s poVAF and ending at serA, has been determined. A contiguous sequence o f 35354bp was established, including previously analysed overlapping a djacent regions. Within the newly determined sequence 31 open reading frames (ORFs) with putative ribosome-binding sites have been found. Ni ne of them correspond to previously sequenced and characterized genes: spoVAF, lysA, sipS, ribG, ribB, ribA, ribH, ribTD and dacB. Compariso n of the amino acid sequences of the products encoded by the other ORF s to known proteins allowed putative functions to be assigned to seven of these ORFs. Among these are the following: (i) the ppiB gene, enco ding a cytoplasmic peptidylprolyl isomerase; (ii) two pairs of signal- transducers, one homologous to phoR-phoP of B. subtilis, encoding regu lators of phosphatase biosynthesis, and the second to the fecI-fecR of Escherichia coli, which is responsible for the regulation of the citr ate-dependent iron (III) transport system; (iii) aroC and serA genes, involved in the biosynthesis of aromatic amino acids and serine, respe ctively, the function of which has been confirmed by constructing corr esponding mutants with disrupted ORFs. The organization of putative op erons has been postulated on the basis of the sequences of their trans cription terminators, promoters and regulatory elements.