Isolation, characterization, and chromosomal location of a gene encoding the Δ¹-pyrroline-5-carboxylate synthetase in Arabidopsis thaliana

A full-length cDNA and the corresponding At-PSS gene encoding the first enzyme of the proline biosynthetic pathway, the Delta(1)-pyrroline-5-carboxylate (P5C) synthetase, mere isolated in Arabidopsis thaliana. The At-P5S cDNA encodes a protein of 717 amino acids showing high identity with the P5C synthetase of Vigna aconitifolia. Strong homology is also found at the N-terminus to bacterial and yeast gamma-glutamyl kinase and at the C-terminus to bacterial gamma-glutamyl phosphate reductase, Putative ATP- and NAD(P)H-binding sites are suggested in the At-PSS protein, The transcribed region of the At-PSS gene is 4.8 kb long and contains 20 exons, Southern analysis suggests the presence of only one At-PSS gene in the A, thaliana genome mapped at the bottom of the chromosome two. Expression analysis of At-P5S in different organs reveals abundant At-PSS transcripts in mature flowering plant, Rapid induction of the Af-PSS gene followed by accumulation of proline was observed in NaCl-treated seedlings suggesting that At-P5S is osmoregulated.A full-length cDNA and the corresponding At-PSS gene encoding the first enzyme of the proline biosynthetic pathway, the Delta(1)-pyrroline-5-carboxylate (P5C) synthetase, mere isolated in Arabidopsis thaliana. The At-P5S cDNA encodes a protein of 717 amino acids showing high identity with the P5C synthetase of Vigna aconitifolia. Strong homology is also found at the N-terminus to bacterial and yeast gamma-glutamyl kinase and at the C-terminus to bacterial gamma-glutamyl phosphate reductase, Putative ATP- and NAD(P)H-binding sites are suggested in the At-PSS protein, The transcribed region of the At-PSS gene is 4.8 kb long and contains 20 exons, Southern analysis suggests the presence of only one At-PSS gene in the A, thaliana genome mapped at the bottom of the chromosome two. Expression analysis of At-P5S in different organs reveals abundant At-PSS transcripts in mature flowering plant, Rapid induction of the Af-PSS gene followed by accumulation of proline was observed in NaCl-treated seedlings suggesting that At-P5S is osmoregulated.A