We have developed a clonal variant, named DF-40, from the N2a mouse neuroblastoma cell line, which has the ornithine decarboxylase (L-ornithine carboxylase, EC 4.1.1.17, ODC) gene amplified. When DF-40 cells were maintained in a simple salt glucose medium (e.g. Earle's blanced salt solution), L-asparagine alone was sufficient to induce a maximal increase in ODC activity. The increase in ODC act...

The human pathogen Staphylococcus aureus is an asparagine prototroph despite its genome not encoding an asparagine synthetase. S. aureus does use an asparaginyl-tRNA synthetase (AsnRS) to directly ligate asparagine to tRNA(Asn). The S. aureus genome also codes for one aspartyl-tRNA synthetase (AspRS). Here we demonstrate the lone S. aureus aspartyl-tRNA synthetase has relaxed tRNA specificity a...

Two point mutants of Chlamydomonas reinhardtii, previously found by recombination and complementation analysis to map in the chloroplast atpB gene encoding the /? subunit of the CFl/CFo ATP synthase, are here shown to be missense alterations near the 5’ end of that gene. One mutant (ac-u-c-2-9) has a change at amino acid position 47 of the /? subunit from leucine (CTA) to arginine (CGA). In the...

Abietadiene synthase catalyzes two sequential, mechanistically distinct cyclization reactions in the formation of a mixture of abietadiene double bond isomers as the committed step in resin acid biosynthesis. Each reaction is carried out at a separate active site residing in a structurally distinct domain, and the reactions are kinetically separable. The first cyclization reaction is initiated ...

Asparaginase is a standard and critical component in the therapy of childhood acute lymphoblastic leukemia. Asparagine synthetase (ASNS) and the basic region leucine zipper activating transcription factor 5 (ATF5) and arginosuccinate synthase 1 (ASS1) have been shown to mediate the antileukemic effect of asparaginase and to display variable expression between leukemia cells that are resistant a...

Asparagine synthetase cDNAs containing the complete coding region were isolated from a human fibroblast cDNA library. DNA sequence analysis of the clones showed that the message contained one open reading frame encoding a protein of 64,400 Mr, 184 nucleotides of 5' untranslated region, and 120 nucleotides of 3' noncoding sequence. Plasmids containing the asparagine synthetase cDNAs were used in...

The proteins of Plasmodium, the malaria parasite, are strikingly rich in asparagine. Plasmodium depends primarily on host haemoglobin degradation for amino acids and has a rudimentary pathway for amino acid biosynthesis, but retains a gene encoding asparagine synthetase (AS). Here we show that deletion of AS in Plasmodium berghei (Pb) delays the asexual- and liver-stage development with substan...