thiBPQ Encodes an ABC Transporter Required for Transport of Thiamine and Thiamine Pyrophosphate inSalmonella typhimurium

Webb, Eric A.; Claas, Kathy R.; Downs, Diana M.

doi:10.1074/jbc.273.15.8946

Cited by 82 publications

(77 citation statements)

References 33 publications

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“…To determine the possible role of the thi box in gene expression, the E. coli genome was searched for the thi box sequence as detailed in Materials and Methods. Interestingly, the thi box sequence was found only in front of the three thiamin biosynthetic operons (thiCEFSGH, thiMD, and thiBPQ), whose expression in S. enterica has been shown to be negatively regulated by TPP (4,12,13). This correlation suggests that the thi box is a regulatory element involved in repression of gene expression by thiamin.…”

Section: Resultsmentioning

confidence: 83%

“…In both organisms the thi genes are located throughout the chromosome and are arranged in three operons and four single gene loci (2). thiCEFSGH, thiMD (ThiM and ThiD are involved in salvage of 5-(2-hydroxyethyl)-4-methyl thiazole and 4-amino-5-hydroxymethyl-2-methyl pyrimidine from the culture medium, respectively; ThiD also catalyzes the phosphorylation of 4-amino-5-hydroxymethyl-2-methyl pyrimidine monophosphate and thiBPQ (which code for an ABC type transport system for thiamin and TPP) are the operons transcriptionally regulated by TPP, whereas the single loci are not regulated (4,12,13). Although some point mutations have been isolated that affect the transcriptional regulation of thi genes, they map at min 10 on the S. enterica chromosome and at least one of them is an allele of thiL gene encoding thiamin monophosphate kinase, suggesting that TPP is the effector molecule involved in regulation of thi gene expression (10,12).…”

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confidence: 99%

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A conserved RNA structure ( thi box) is involved in regulation of thiamin biosynthetic gene expression in bacteria

Miranda-Ríos

Navarro²,

Soberón³

2001

Proc. Natl. Acad. Sci. U.S.A.

230

153

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The thiCOGE genes of Rhizobium etli code for enzymes involved in thiamin biosynthesis. These genes are transcribed with a 211-base untranslated leader that contains the thi box, a 38-base sequence highly conserved in the 5 regions of thiamin biosynthetic and transport genes of Gram-positive and Gram-negative organisms. A deletion analysis of thiC-lacZ fusions revealed an unexpected relationship between the degree of repression shown by the deleted derivatives and the length of the thiC sequences present in the transcript. Three regions were found to be important for regulation: (i) the thi box sequence, which is absolutely necessary for high-level expression of thiC; (ii) the region immediately upstream to the translation start codon of thiC, which can be folded into a stem-loop structure that would mask the Shine-Dalgarno sequence; and (iii) the proximal part of the coding region of thiC, which was shown to contain a putative Rho-independent terminator. A comparative phylogenetic analysis revealed a possible folding of the thi box sequence into a hairpin structure composed of a hairpin loop, two helixes, and an interior loop. Our results show that thiamin regulation of gene expression involves a complex posttranscriptional mechanism and that the thi box RNA structure is indispensable for thiCOGE expression.T hiamin pyrophosphate (TPP), also known as cocarboxylase, is the cofactor of key enzymes of carbon metabolism such as pyruvate dehydrogenase, ␣-ketoglutarate dehydrogenase, transketolase, pyruvate decarboxylase, and others. TPP is made by the enzymatic coupling of two independently synthesized precursors, 4-amino-5-hydroxymethyl-2-methyl pyrimidine pyrophosphate and 5-(2-hydroxyethyl)-4-methyl thiazole monophosphate (1).In Escherichia coli and Salmonella enterica serovar Typhimurium, several genes are known to participate in TPP biosynthesis (2). thiC and thiD are required for 4-amino-5-hydroxymethyl-2-methyl pyrimidine pyrophosphate synthesis (3, 4), whereas dxs (5, 6), thiF, thiS, thiG, thiH, and thiI are involved in 5-(2-hydroxyethyl)-4-methyl thiazole monophosphate synthesis (3,7,8). In addition, the product of the thiE gene couples 4-amino-5-hydroxymethyl-2-methyl pyrimidine pyrophosphate and 5-(2-hydroxyethyl)-4-methyl thiazole monophosphate to give thiamin monophosphate, which undergoes another phosphorylation catalyzed by the product of the thiL gene to form TPP, the biologically active form of vitamin B 1 (9, 10). A salvage enzyme (thiamin kinase) encoded by thiK, which incorporates exogenous thiamin into TPP (11), also exists. In both organisms the thi genes are located throughout the chromosome and are arranged in three operons and four single gene loci (2). thiCEFSGH, thiMD (ThiM and ThiD are involved in salvage of 5-(2-hydroxyethyl)-4-methyl thiazole and 4-amino-5-hydroxymethyl-2-methyl pyrimidine from the culture medium, respectively; ThiD also catalyzes the phosphorylation of 4-amino-5-hydroxymethyl-2-methyl pyrimidine monophosphate and thiBPQ (which code for an ABC type transport system for t...

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Section: Resultsmentioning

confidence: 83%

mentioning

confidence: 99%

A conserved RNA structure ( thi box) is involved in regulation of thiamin biosynthetic gene expression in bacteria

Miranda-Ríos

Navarro²,

Soberón³

2001

Proc. Natl. Acad. Sci. U.S.A.

230

153

View full text Add to dashboard Cite

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“…ABC-T SMc02509 was induced by both manganese and iron limitation (Ϸ110-fold) and is the identified manganese transporter (Sit) from S. meliloti (38). ABC-T SMc03869 was induced by thiamine limitation (11-fold) and has 57% identity with the characterized thiamine transporter (Thi) from S. typhimurium (39). ABC-T SMc03196, induced 12-fold by molybdate limitation, has 58% identity with the characterized molybdate transporter (Mod) from B. japonicum (40).…”

Section: Site the Results Are Shown In Full Inmentioning

confidence: 99%

Mapping the Sinorhizobium meliloti 1021 solute-binding protein-dependent transportome

Mauchline

Fowler

East

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

138

146

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The number of solute-binding protein-dependent transporters in rhizobia is dramatically increased compared with the majority of other bacteria so far sequenced. This increase may be due to the high affinity of solute-binding proteins for solutes, permitting the acquisition of a broad range of growth-limiting nutrients from soil and the rhizosphere. The transcriptional induction of these transporters was studied by creating a suite of plasmid and integrated fusions to nearly all ATP-binding cassette (ABC) and tripartite ATP-independent periplasmic (TRAP) transporters of Sinorhizobium meliloti. In total, specific inducers were identified for 76 transport systems, amounting to Ϸ47% of the ABC uptake systems and 53% of the TRAP transporters in S. meliloti. Of these transport systems, 64 are previously uncharacterized in Rhizobia and 24 were induced by solutes not known to be transported by ABC-or TRAP-uptake systems in any organism. This study provides a global expression map of one of the largest transporter families (transportome) and an invaluable tool to both understand their solute specificity and the relationships between members of large paralogous families.ATP-binding cassette ͉ expression ͉ high throughput ͉ transport ͉ tripartite ATP-independent periplasmic

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“…HIMB59, thiC, thiD, thiG, thiE and thiE2 and thiS are absent. However, a gene encoding a thiamin-specific periplasmic binding protein (thiB) (Webb et al, 1998) was identified in HIMB59 (Table 1).…”

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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thiBPQ Encodes an ABC Transporter Required for Transport of Thiamine and Thiamine Pyrophosphate inSalmonella typhimurium

Cited by 82 publications

References 33 publications

A conserved RNA structure ( thi box) is involved in regulation of thiamin biosynthetic gene expression in bacteria

A conserved RNA structure ( thi box) is involved in regulation of thiamin biosynthetic gene expression in bacteria

Mapping the Sinorhizobium meliloti 1021 solute-binding protein-dependent transportome

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

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