ISSN:
1617-4623
Keywords:
Neurospora crassa
;
Pyrroline-5-carboxylate reductase
;
Proline biosynthesis
;
Cross-pathway control
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Δ1-pyrroline-5-carboxylate reductase (P5CR; [l-proline: NAD(P+) 5-oxidoreductase]; EC 1.5.1.2) catalyzes the final step in proline biosynthesis. We have shown that theproline-1 (pro-1) locus ofNeurospora crassa encodes P5CR. Thepro-1 gene was localized to a 3.2 kb region by complementation of (restoration of proline-independent growth to) a proline auxotroph carrying a recessive mutation at thepro-1 locus. The nucleotide sequence of this 3.2 kb region contains an open reading frame with coding capacity of 311 amino acids. The deduced polypeptide shows significant similarity to P5CR amino acid sequences. Similarity ofN. crassa P5CR is greatest to that of the yeast,Saccharomyces cerevisiae, but is also strong to P5CR sequences from archaea, eubacteria, plants, and humans. InN. crassa, amino acid imbalance, including deficiency or excess of a single amino acid, such as histidine, induces expression of many amino acid biosynthetic genes that are under cross-pathway control, a general regulatory system analogous to general amino acid control inSaccharomyces. Although P5CR catalyzes the only committed step in proline biosynthesis,pro-1 expression was unaltered by histidine starvation and independent of CPC1, a positively acting transcription factor that mediates cross-pathway control inN. crassa.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02191601
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