Identification of the gene (aroK) encoding shikimic acid kinase I of Escherichia coli.

DNA sequence analysis has revealed that an unidentified open reading frame (ufr1) is present immediately preceding the aroB gene of Escherichia coli. The predicted protein product of urf1 contains a consensus ATP-binding-site sequence and shows 34% amino acid homology to shikimate kinase II in a 97-amino-acid region. Inactivation of urf1 by insertion of an antibiotic resistance gene had a polar effect on aroB, indicating that these two genes constitute a transcriptional unit. The auxotrophic requirements of a strain mutant for both urf1 and aroL (encoding shikimate kinase II) are consistent with shikimate kinase deficiency. We propose that urf1 encodes shikimate kinase I and that it be designated aroK.