Disease relevance of argI

• Homologous control sites and DNA transcription starts in the related argF and argI genes of Escherichia coli K12 [1].
• Comparison of the N-terminal amino acid sequence of the E. coli anabolic ornithine carbamoyltransferase with that of the A. formicans and Pseudomonas putida catabolic enzymes shows, respectively, 45 and 28% identity between the compared positions; the A. formicans sequence reveals 53% identity with the Pseudomonas putida sequence [2].
• Among the Enterobacteriaceae, Escherichia coli K-12 is the only strain known to have two structural genes (argF and argI) for ornithine carbamoyltransferase [3].
• Molecular cloning, characterization and purification of ornithine carbamoyltransferase from Mycobacterium bovis BCG [4].
• Metabolic enzymes from psychrophilic bacteria: challenge of adaptation to low temperatures in ornithine carbamoyltransferase from Moritella abyssi [5].

High impact information on argI

• Thus, in catabolic OTCase, sequence features in addition to Glu-106 are important for sigmoidal CP saturation, and such a sequence was identified in the C-terminal part [6].
• In the anabolic OTCase of Escherichia coli the glutamine residue corresponding to Glu-106 was exchanged for glutamate; however, in this case no CP cooperativity was acquired [6].
• The catabolic OTCase lost most of its homotropic cooperativity and gained anabolic activity when an amino acid residue near the CP binding site, Glu-106, was replaced by alanine or glycine [6].
• By an in vivo gene fusion technique the 9 C-terminal amino acids of catabolic OTCase were replaced by the homologous 8 amino acids from anabolic OTCase of E. coli; the hybrid enzyme had a markedly reduced homotropic cooperativity [6].
• An altered form of argI was produced when a 1.6 kilobase DdeI fragment was subcloned into the HincII site of plasmid pUC8 extending the open reading frame an additional 20 nucleotides [7].

Chemical compound and disease context of argI

• Escherichia coli strains capable of enhanced synthesis of arginine and urea were produced by derepression of the arginine regulon and simultaneous overexpression of the E. coli carAB and argI genes and the Bacillus subtilis rocF gene [8].
• Starvation for phenylalanine led to leucine misincorporation frequencies of 0.1 and 0.6 at UUC codons in the argI transcript of Escherichia coli, but no detectable misincorporation at a UUU codon [9].
• It has previously been shown that the phenylalanine codon UUC encoding residue 8 of the Escherichia coli argI gene product, ornithine transcarbamylase, is misread as leucine at a high frequency during phenylalanine starvation [10].
• Phaseolotoxin [(N delta-phosphosulfamyl)ornithylalanylhomoarginine], a phytotoxic tripeptide produced by Pseudomonas syringae pv. phaseolicola that inhibits ornithine carbamoyltransferase, is transported into Escherichia coli and Salmonella typhimurium via the oligopeptide transport system (Opp) [11].

Biological context of argI

• DNA cleavage of lambda and phi 80 transducing phages carrying the argA, argECBH, argF and argI operons of Escherichia coli K-12 with the restriction endonucleases EcoRI, SmaI and HindIII [12].
• Arginine operator sequences (Arg boxes) from argI were also cloned into the same plasmids for titration of the arginine repressor [8].
• The bearing of the available information regarding ornithine carbamoyltransferase isoenzymes on the evolution of the ancestral E. coli chromosome is reconsidered [3].
• Linker insertion mutagenesis based on IS21 transposition: isolation of an AMP-insensitive variant of catabolic ornithine carbamoyltransferase from Pseudomonas aeruginosa [13].
• When Glu1O5 and nine C-terminal amino acids of the catabolic OTCase were introduced, by in vitro genetic manipulation, into the closely related, trimeric, anabolic (ArgF) OTCase of Escherichia coli, the enzyme displayed Michaelis-Menten kinetics and no cooperativity was observed [14].

Associations of argI with chemical compounds

• Citrulline utilizers are argG bradytrophs or strains in which the synthesis of ornithine carbamoyltransferase (either of the F or I type) is specifically depressed by unstable chromosomal rearrangements or stable mutations that presumably affect the operators of those genes [15].
• Using these mutant argI genes we see a high level of mistranslation at position 8 during phenylalanine starvation whether the codon is UUU or UUC [10].
• Several arg+ transformants of integration types I and II, obtained using each of the deletion plasmids, were studied, and their ability to de-repress OTC level by proline starvation was compared [16].
• Activation by AMP and inhibition by spermidine of this chimaeric OTCase do not affect carbamoylphosphate homotropic co-operativity [17].

Other interactions of argI

• We have constructed a series of deletion plasmids which contain the Aspergillus nidulans argB gene for ornithine carbamoyltransferase (OTC) [16].

Analytical, diagnostic and therapeutic context of argI

• The minimum inhibitory concentration of kanamycin determined in the B. subtilis argC-neo transcriptional fusion pUL730 and expression of the argF gene product, ornithine carbamoyltransferase (OCTase), in pUL800 were reduced by approximately 3 and 2 fold respectively under conditions of arginine excess and in the presence of pUL2030 [18].
• Hybridization results and immunological tests indicate that the cloned fragment contains the A. nidulans structural gene coding for ornithine carbamoyltransferase (OTCase) [19].
• CONCLUSIONS: Our newly established ELISA for OCT using monoclonal antibodies is sensitive enough for clinical application [20].

References