The purH and purD genes coding for the 5′-phosphoribosyl 5-amino-imidazole-4-carboxamide (AICAR) transformylase and 5′-phosphoribosyl-glycinamide (GAR) synthetase, respectively, were identified on a 4.8 kb EcoRI fragment of chromosomal DNA from Salmonella typhimurium. Nucleotide sequence analysis of the cloned fragment revealed the presence of two large open reading frames (O.R.F.), which were separated by 11 base pairs (bp). Substantial DNA and amino acid sequence homology was noted between the purH and purD genes of S. typhimurium and Escherichia coli. Expression of the Salmonella purD gene in a T7 polymerase/promoter system revealed the presence of a 49 kDa protein band by SDS-PAGE and subsequent autoradiography. The purH gene of Salmonella was not expressed since the 5′ end of this gene was not cloned.
- DNA sequencing
- purH and purD genes
- T7 polymerase/promoter system
ASJC Scopus subject areas
- Structural Biology