Figure 3

Organization of the arginine operon in X. campestris and amino acid sequence conservation between NAGS-K and both NAGS and NAGK. A. The arginine operon in X. campestris. ArgC, argD, argG and argH genes were identified based on their similarity with homologs in other bacteria. ArgF' encodes acetylornithine transcarbamylase (AOTCase) and argE gene product can catalyze deacetylation of acetylornithine as well as acetylcitrulline [7]. The argA gene was annotated based on its similarity with other acetyltransferases. Genes labeled with question marks encode hypothetical proteins of unknown function. ArgD gene is located elsewhere in the genome and not in the same cluster as other eight genes. B. Alignment of NAGS from mouse, S. cerevisiae and S. pombe, NAGS-K from X. campestris, and NAGK from T. maritima, E. coli, S. cerevisiae and S. pombe. Residues that are important for catalysis of NAGK are shown in red. Residues that are conserved in vertebrate and fungal NAGS are shown in green. Residues that are mutated in patients with NAGS deficiency are highlighted in grey. Conserved residues that are presumed to be part of AcCoA binding site are shown in blue.