Biosynthesis of .BETA.-(isoxazolin-5-on-2-yl) alanine, the precursor of the neurotoxic amino acid .BETA.-N-oxalyl-L-.ALPHA.,.BETA.-diaminopropionic acid.

Abstract

beta-(Isoxazolin-5-on-2-yl)alanine (BIA), a biosynthetic precursor of the neurotoxic amino acid beta-N-oxalyl-L-alpha,beta-diaminopropionic acid (ODAP), was confirmed to be derived from O-acetyl-L-serine (OAS) and isoxazolin-5-one by cysteine synthase in higher plants. Some properties of this enzyme in the biosynthesis of BIA are described.

β-Cyanoalanine Synthase Regulates the Accumulation of β-ODAP via Interaction with Serine Acetyltransferase in Lathyrus sativus

“…The column was washed rigorously with 20 mM Tris−HCl (pH 7.5, containing 500 mM NaCl and 50 mM imidazole) to remove the unbound proteins and the bound protein complex was eluted with 150 mM imidazole. The eluted protein complex was concentrated using an Amicon-Ultra- 15 For imaging GFP fluorescence or mCherry, the 488 nm excitation and 598 nm emission spectra or the 561 nm excitation and 670 nm emission spectra were used, respectively. mt-rk (GV3101-CD3-991-mCherry, localized in mitochondria) was used as a positive control.…”

“…13,14 β-ODAP biosynthesis begins with the formation of β-(isoxazolin-5-on-2-yl) alanine (BIA) from the reaction of O-acetylserine (OAS) and isoxazolin-5one. 15,16 Subsequently, BIA spontaneously degrades to L-2,3diaminopropionic acid (L-DAP) and forms β-ODAP with oxalyl-CoA catalyzed by BAHD3 acyltransferase. 17,18 In this β-ODAP biosynthesis pathway, β-cyanoalanine synthase (β-CAS) was thought to be the critical enzyme 19 and regulate the flux between sulfur and nitrogen assimilatory pathways.…”

“…sativus was thought crucial to cause lathyrism in the presence of β-ODAP . Recent metabolomics and transcriptomic studies on the biosynthesis of β-ODAP have shown a link with primary metabolism, especially sulfur metabolism. , β-ODAP biosynthesis begins with the formation of β-(isoxazolin-5-on-2-yl) alanine (BIA) from the reaction of O -acetylserine (OAS) and isoxazolin-5-one. , Subsequently, BIA spontaneously degrades to l -2,3-diaminopropionic acid ( l -DAP) and forms β-ODAP with oxalyl-CoA catalyzed by BAHD3 acyltransferase. , In this β-ODAP biosynthesis pathway, β-cyanoalanine synthase (β-CAS) was thought to be the critical enzyme and regulate the flux between sulfur and nitrogen assimilatory pathways. ,, …”

β-N-Oxalyl-l-α,β-diaminopropionic Acid (β-ODAP) Content in Lathyrus sativus: The Integration of Nitrogen and Sulfur Metabolism through β-Cyanoalanine Synthase

“…The enzymatic pathway of β-ODAP biosynthesis is not fully understood [40,41]. It is believed that its synthesis begins with formation of β-(isoxazolin-5-on-2-yl)alanine from reaction of O -acetylserine and isoxazolin-5-one (Figure 2).…”

“…It is believed that its synthesis begins with formation of β-(isoxazolin-5-on-2-yl)alanine from reaction of O -acetylserine and isoxazolin-5-one (Figure 2). Early studies suggest that β-cyanoalanine synthase (CAS) uses isoxazolin-5-one as an alternative nucleophile in the reaction [40,41]. Next, β-(isoxazolin-5-on-2-yl)alanine (BIA) is proposed to be converted to the short-lived intermediate 2,3,- l -diaminopropanoic acid, which is subsequently oxalylized by oxalyl-coenzyme A to form β-ODAP [42,43,44,45].…”