The THI5 gene family of Saccharomyces cerevisiae: distribution of homologues among the hemiascomycetes and functional redundancy in the aerobic biosynthesis of thiamin from pyridoxine

Wightman, Raymond; Meacock, Peter A.

doi:10.1099/mic.0.26194-0

Cited by 85 publications

(75 citation statements)

References 42 publications

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“…For example, Ca. P. ubique lacks genes encoding for NMT1, which synthesizes HMP from vitamin B 6 and histidine in Saccharomyces cerevisiae (Figure 1) (Wightman and Meacock, 2003). Genes encoding TenA homologs, which catalyze the hydrolysis of AmMP to yield HMP (Jenkins et al, 2007), were also not present in Ca.…”

Section: Resultsmentioning

confidence: 99%

Discovery of a SAR11 growth requirement for thiamin’s pyrimidine precursor and its distribution in the Sargasso Sea

et al. 2014

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Vitamin traffic, the production of organic growth factors by some microbial community members and their use by other taxa, is being scrutinized as a potential explanation for the variation and highly connected behavior observed in ocean plankton by community network analysis. Thiamin (vitamin B1), a cofactor in many essential biochemical reactions that modify carbon–carbon bonds of organic compounds, is distributed in complex patterns at subpicomolar concentrations in the marine surface layer (0–300 m). Sequenced genomes from organisms belonging to the abundant and ubiquitous SAR11 clade of marine chemoheterotrophic bacteria contain genes coding for a complete thiamin biosynthetic pathway, except for thiC, encoding the 4-amino-5-hydroxymethyl-2-methylpyrimidine (HMP) synthase, which is required for de novo synthesis of thiamin’s pyrimidine moiety. Here we demonstrate that the SAR11 isolate ‘Candidatus Pelagibacter ubique’, strain HTCC1062, is auxotrophic for the thiamin precursor HMP, and cannot use exogenous thiamin for growth. In culture, strain HTCC1062 required 0.7 zeptomoles per cell (ca. 400 HMP molecules per cell). Measurements of dissolved HMP in the Sargasso Sea surface layer showed that HMP ranged from undetectable (detection limit: 2.4 pm) to 35.7 pm, with maximum concentrations coincident with the deep chlorophyll maximum. In culture, some marine cyanobacteria, microalgae and bacteria exuded HMP, and in the Western Sargasso Sea, HMP profiles changed between the morning and evening, suggesting a dynamic biological flux from producers to consumers.

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Section: Resultsmentioning

confidence: 99%

Discovery of a SAR11 growth requirement for thiamin’s pyrimidine precursor and its distribution in the Sargasso Sea

et al. 2014

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“…Four genes, SNO2/SNO3 and SNZ2/SNZ3, are possibly involved in the synthesis of pyridoxal phosphate, the common precursor of other B 6 vitamers and HMP-P [13]. Later steps of HMP-P synthesis up till the final HMP-P phosphorylation are controlled by genes of the THI5/THI11/THI12/THI13 family [19] and the PET18 gene, but the exact enzymatic functions of their protein products have not yet been recognized. The members of another gene family, THI20 and THI21, encode HMP-P kinases, which are actually trifunctional proteins, as they can also perform the salvage HMP phosphorylation, and contain an additional C-terminal domain with a thiamin degrading (thiaminase II) activity [14,20].…”

Section: The Genetic Control Of Thiamin Biosynthesis In Yeastsmentioning

confidence: 99%

The genes and enzymes involved in the biosynthesis of thiamin and thiamin diphosphate in yeasts

Kowalska

Kozik

2008

Cellular and Molecular Biology Letters

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Thiamin (vitamin B1) is an essential molecule for all living organisms. Its major biologically active derivative is thiamin diphosphate, which serves as a cofactor for several enzymes involved in carbohydrate and amino acid metabolism. Important new functions for thiamin and its phosphate esters have recently been suggested, e.g. in gene expression regulation by influencing mRNA structure, in DNA repair after UV illumination, and in the protection of some organelles against reactive oxygen species. Unlike higher animals, which rely on nutritional thiamin intake, yeasts can synthesize thiamin de novo. The biosynthesis pathways include the separate synthesis of two precursors, 4-amino -5-hydroxymethyl-2-methylpyrimidine diphosphate and 5-(2-hydroxyethyl)-4-methylthiazole phosphate, which are then condensed into thiamin monophosphate. Additionally, yeasts evolved salvage mechanisms to utilize thiamin and its dephosphorylated late precursors, 4-amino-5-hydroxymethyl-2-methylpyrimidine and 5-(2-hydroxyethyl)-4-methylthiazole, from the environment. The current state of knowledge on the discrete steps of thiamin biosynthesis in yeasts is far from satisfactory; many intermediates are postulated only by analogy to the much better understood biosynthesis process in bacteria. On the other hand, the genetic mechanisms regulating thiamin biosynthesis in yeasts are currently under extensive exploration. Only recently, the structures of some of the yeast enzymes involved in thiamin biosynthesis, such as thiamin diphosphokinase and thiazole synthase, were determined at the atomic resolution, and mechanistic proposals for the catalysis of particular biosynthetic steps started to emerge.

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“…Pyrimidine biosynthesis is more complicated in yeast than in prokaryotes. Four genes (THI5, THI11, THI12 and THI13) have been reported to be involved in this step [22,23].…”

Section: Introductionmentioning

confidence: 99%

AtTHIC, a gene involved in thiamine biosynthesis in Arabidopsis thaliana

Kong

Zhu

et al. 2008

Cell Res

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Thiamine (vitamin B1) is an essential compound for organisms. It contains a pyrimidine ring structure and a thiazole ring structure. These two moieties of thiamine are synthesized independently and then coupled together. Here we report the molecular characterization of AtTHIC, which is involved in thiamine biosynthesis in Arabidopsis. AtTHIC is similar to Escherichia coli ThiC, which is involved in pyrimidine biosynthesis in prokaryotes. Heterologous expression of AtTHIC could functionally complement the thiC knock-out mutant of E. coli. Downregulation of AtTHIC expression by T-DNA insertion at its promoter region resulted in a drastic reduction of thiamine content in plants and the knock-down mutant thic1 showed albino (white leaves) and lethal phenotypes under the normal culture conditions. The thic1 mutant could be rescued by supplementation of thiamine and its defect functions could be complemented by expression of AtTHIC cDNA. Transient expression analysis revealed that the AtTHIC protein targets plastids and chloroplasts. AtTHIC was strongly expressed in leaves, flowers and siliques and the transcription of AtTHIC was downregulated by extrinsic thiamine. In conclusion, AtTHIC is a gene involved in pyrimidine synthesis in the thiamine biosynthesis pathway of Arabidopsis, and our results provide some new clues for elucidating the pathway of thiamine biosynthesis in plants.

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The THI5 gene family of Saccharomyces cerevisiae: distribution of homologues among the hemiascomycetes and functional redundancy in the aerobic biosynthesis of thiamin from pyridoxine

Cited by 85 publications

References 42 publications

Discovery of a SAR11 growth requirement for thiamin’s pyrimidine precursor and its distribution in the Sargasso Sea

Discovery of a SAR11 growth requirement for thiamin’s pyrimidine precursor and its distribution in the Sargasso Sea

The genes and enzymes involved in the biosynthesis of thiamin and thiamin diphosphate in yeasts

AtTHIC, a gene involved in thiamine biosynthesis in Arabidopsis thaliana

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