Disease relevance of aat

• Previous work has shown that, in the bacterium Escherichia coli, the aat gene is essential for the degradation of proteins bearing amino-terminal Arg and Lys residues via the N-end rule pathway of protein degradation [1].
• To prove the essential involvement of the fcs, ech, and aat genes in the catabolism of ferulic acid and eugenol in Pseudomonas sp. strain HR199, these genes were inactivated separately by the insertion of omega elements [2].

High impact information on aat

• Eubacterial leucyl/phenylalanyl-tRNA protein transferase (L/F-transferase), encoded by the aat gene, conjugates leucine or phenylalanine to the N-terminal Arg or Lys residue of proteins, using Leu-tRNA(Leu) or Phe-tRNA(Phe) as a substrate [3].
• The aat gene maps to the 19-min region of the E. coli chromosome and encodes a 234-residue protein whose sequence lacks significant similarities to sequences in data bases [4].
• In the heterologous, nonpenicillin producer A. niger, basal expression of aat-lacZ gene fusions was observed at about the same level as in A. nidulans [5].
• Using the HEp-2 adhesion assay as the gold standard, the addition of primers detecting aaiA and astA to the aat PCR increased the number of EAEC isolates detected, but identified strains of E. coli that were not EAEC [6].
• The isolates harbouring these genes were also tested using the HEp-2 cell-adhesion assay to clarify their EAEC status. aat, aai or astA was found in E. coli faecal isolates from 39 (7.8 %) of 500 patients, and 20 of these strains adhered to HEp-2 cells in a pattern characteristic of EAEC [6].

Biological context of aat

• Eight isolates carrying the aai or astA gene but not the aat gene were shown to be HEp-2 cell test positive, although 12 strains with this genotype were HEp-2 cell test negative [6].

Associations of aat with chemical compounds

• Although AAT specific activity was reduced in mycelia grown on glucose instead of lactose, expression of aat-lacZ gene fusions was not repressed on glucose, suggesting that the glucose effect is mediated posttranscriptionally [5].
• The aat gene product was shown not to be involved in this catabolism, thus excluding a beta-oxidation analogous degradation pathway for ferulic acid [2].

Analytical, diagnostic and therapeutic context of aat

• The aim of this study was to assess the usefulness of a multiplex PCR assay targeting the aat, aaiA and astA genes for the detection of typical and atypical enteroaggregative Escherichia coli (EAEC) in bacterial cultures from faecal samples from patients with community-acquired diarrhoea [6].

References