scholarly journals Revision in the first steps of the biosynthesis of the red antibiotic prodigiosin: use of a synthetic thioester to validate a new intermediate

2021 ◽  
Author(s):  
Maxime Couturier ◽  
Hiral D. Bhalara ◽  
Rita E. Monson ◽  
George P. C. Salmond ◽  
Finian J. Leeper
Keyword(s):  
Biosynthetic Pathway ◽  
Red Pigment

A revision is proposed to the biosynthetic pathway to the well-known red pigment prodigiosin via a new thioester intermediate.

scholarly journals apd1  +, a Gene Required for Red Pigment Formation in ade6 Mutants of Schizosaccharomyces pombe, Encodes an Enzyme Required for Glutathione Biosynthesis: A Role for Glutathione and a Glutathione-Conjugate Pump

Genetics ◽  
1997 ◽  
Vol 145 (1) ◽  
pp. 75-83 ◽  
Author(s):  
Biswendu Chaudhuri ◽  
Susham Ingavale ◽  
Anand K Bachhawat
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Schizosaccharomyces Pombe ◽  
Biosynthetic Pathway ◽  
Glutathione Synthetase ◽  
Red Pigment ◽  
Genetic Investigation ◽  
Pigment Formation ◽  
Glutathione Conjugate ◽  
Glutathione Biosynthesis ◽  
Glutamylcysteine Synthetase

Mutants in the adenine biosynthetic pathway of yeasts (ade1 and ade2 of Saccharomyces cerevisiae, ade6 and ade7 of Schizosaccharomyces pombe) accumulate an intense red pigment in their vacuoles when grown under adenine-limiting conditions. The precise events that determine the formation of the pigment are however, still unknown. We have begun a genetic investigation into the nature and cause of pigmentation of ade6 mutants of S. pombe and have discovered that one of these pigmentation defective mutants, apd1 (adenine pigmentation defective), is a strict glutathione auxotroph. The gene apd1  + was found to encode the first enzyme in glutathione biosynthesis, γ-glutamylcysteine synthetase, gcs1  +. This gene when expressed in the mutant could confer both glutathione prototrophy and the characteristic red pigmentation, and disruption of the gene led to a loss in both phenotypes. Supplementation of glutathione in the medium, however, could only restore growth but not the pigmentation because the cells were unable to achieve sufficient intracellular levels of glutathione. Disruption of the second enzyme in glutathione biosynthesis, glutathione synthetase, gsh2  +, also led to glutathione auxotrophy, but only a partial defect in pigment formation. A reevaluation of the major amino acids previously reported to be present in the pigment indicated that the pigment is probably a glutathione conjugate. The ability of vanadate to inhibit pigment formation indicated that the conjugate was transported into the vacuole through a glutathione-conjugate pump. This was further confirmed using strains of S. cerevisiae bearing disruptions in the recently identified glutathione-conjugate pump, YCF1, where a significant reduction in pigment formation was observed. The pump of S. pombe is distinct from the previously identified vacuolar pump, hmt1p, for transporting cadystin peptides into vacuoles of S. pombe.

scholarly journals Engineering Betalain Biosynthesis in Tomato for High Level Betanin Production in Fruits

2021 ◽  
Vol 12 ◽  
Author(s):  
Ramona Grützner ◽  
Ramona Schubert ◽  
Claudia Horn ◽  
Changqing Yang ◽  
Thomas Vogt ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Biosynthetic Pathway ◽  
Feedback Inhibition ◽  
Red Pigment ◽  
Tomato Plants ◽  
Dehydrogenase Gene ◽  
Yellow Orange ◽  
Arogenate Dehydrogenase ◽  
High Level ◽  
Level Production

Betalains are pigments found in plants of the Caryophyllales order, and include the red-purple betacyanins and the yellow-orange betaxanthins. The red pigment from red beets, betanin, is made from tyrosine by a biosynthetic pathway that consists of a cytochrome P450, a L-DOPA dioxygenase, and a glucosyltransferase. The entire pathway was recently reconstituted in plants that do not make betalains naturally including potato and tomato plants. The amount of betanin produced in these plants was however not as high as in red beets. It was recently shown that a plastidic arogenate dehydrogenase gene involved in biosynthesis of tyrosine in plants is duplicated in Beta vulgaris and other betalain-producing plants, and that one of the two encoded enzymes, BvADHα, has relaxed feedback inhibition by tyrosine, contributing to the high amount of betanin found in red beets. We have reconstituted the complete betanin biosynthetic pathway in tomato plants with or without a BvADHα gene, and with all genes expressed under control of a fruit-specific promoter. The plants obtained with a construct containing BvADHα produced betanin at a higher level than plants obtained with a construct lacking this gene. These results show that use of BvADHα can be useful for high level production of betalains in heterologous hosts. Unlike red beets that produce both betacyanins and betaxanthins, the transformed tomatoes produced betacyanins only, conferring a bright purple-fuschia color to the tomato juice.

New insights into heparan sulphate biosynthesis from the study of mutant mice

2002 ◽  
Vol 69 ◽  
pp. 47-57 ◽  
Author(s):  
Catherine L. R. Merry ◽  
John T. Gallagher
Keyword(s):  
Growth Factors ◽  
Biosynthetic Pathway ◽  
Heparan Sulphate ◽  
Mutant Mice ◽  
Gene Products ◽  
Multiple Gene ◽  
Adhesion Proteins ◽  
Ligand Interactions

Heparan sulphate (HS) is an essential co-receptor for a number of growth factors, morphogens and adhesion proteins. The biosynthetic modifications involved in the generation of a mature HS chain may determine the strength and outcome of HS–ligand interactions. These modifications are catalysed by a complex family of enzymes, some of which occur as multiple gene products. Various mutant mice have now been generated, which lack the function of isolated components of the HS biosynthetic pathway. In this discussion, we outline the key findings of these studies, and use them to put into context our own work concerning the structure of the HS generated by the Hs2st-/- mice.

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