Cloning and characterization of the Mycobacterium bovis BCG panB gene encoding ketopantoate hydroxymethyltransferase

The Mycobacterium bovis BCG panB gene, encoding ketopantoate hydroxymethyltransferase (KPHMT), was cloned from a lambda gt11 genomic library and sequenced. The DNA sequence encodes a protein that contains 281 amino acid residues (M-r 29,337) with a high similarity to the KPBMTs. Subcloning of a 846 bp open reading frame (ORF), but not a 735 bp ORF, into the vector pUC19 led to complementation of the panB mutant of Escherichia coli. The BCG panB gene was overexpressed in E. coli and the KPHMT purified to homogeneity. The recombinant protein was further confirmed by an enzymatic assay.