menaquinone-6 and 1-4-dihydroxy-2-naphthoic-acid

Topics: Animals; Bacillus subtilis; Bacteria; Escherichia coli; Genes, Bacterial; Intestines; Ketoglutaric Acids; Lactobacillus; Methylation; Mycobacterium; Naphthols; Oxygen; Phenylbutyrates; Prevotella melaninogenica; Shikimic Acid; Staphylococcus aureus; Vitamin K; Vitamin K 2

The enzyme 1, 4-dihydroxy-2-naphthoic acid (DHNA) prenyltransferase (MenA) is a critical player in determining the efficiency of the menaquinone (MK) synthesis pathway and is an attractive target for the development of novel chemotherapeutics against pathogenic Gram-positive bacteria. However, there has been no report on structural properties or active region of MenA. To solve this challenge, we predicted the three-dimensiona structure and critical amino acid sites of MenA by bioinformatics analysis. Six amino acid sites were chosen by alligning the amino acid sequence of MenA from Bacillus subtilis natto with 4-hydroxybenzoate octaprenyl transferase (UbiA) from Escherichia coli, Aeropyrum pernix and Archaeoglobus fulgidus. Among them, four Asp sites located in two Asp-rich motifs (D

Topics: Amino Acid Sequence; Bacillus subtilis; Bacterial Proteins; Catalytic Domain; Dimethylallyltranstransferase; Escherichia coli; Fermentation; Hydrophobic and Hydrophilic Interactions; Kinetics; Models, Molecular; Mutation; Naphthols; Recombinant Proteins; Vitamin K 2

Topics: Animals; Cytosol; Disease Models, Animal; Listeria monocytogenes; Listeriosis; Mice; Microbial Viability; Mutant Proteins; Naphthols; Suppression, Genetic; Transcription Factors; Virulence; Vitamin K 2; Whole Genome Sequencing

Through unknown mechanisms, the host cytosol restricts bacterial colonization; therefore, only professional cytosolic pathogens are adapted to colonize this host environment.

Topics: DNA Transposable Elements; Genetic Testing; Listeria monocytogenes; Metabolic Networks and Pathways; Microbial Viability; Mutagenesis, Insertional; Mutation; Naphthols; Vitamin K 2

Topics: Batch Cell Culture Techniques; Biocatalysis; Biotransformation; Cell Culture Techniques; Cells, Immobilized; Farnesol; Flavobacteriaceae; Genetic Engineering; Naphthols; Vitamin K 2

Aerobic respiration metabolism in Group B Streptococcus (GBS) is activated by exogenous heme and menaquinone. This capacity enhances resistance of GBS to acid and oxidative stress and improves its survival. In this work, we discovered that GBS is able to respire in the presence of heme and 1,4-dihydroxy-2-naphthoic acid (DHNA). DHNA is a biosynthetic precursor of demethylmenaquinone (DMK) in many bacterial species. A GBS gene (gbs1789) encodes a homolog of the MenA 1,4-dihydroxy-2-naphthoate prenyltransferase enzyme, involved in the synthesis of demethylmenaquinone. In this study, we showed that gbs1789 is involved in the biosynthesis of long-chain demethylmenaquinones (DMK-10). The Δgbs1789 mutant cannot respire in the presence of heme and DHNA, indicating that endogenously synthesized DMKs are cofactors of the GBS respiratory chain. We also found that isoprenoid side chains from GBS DMKs are produced by the protein encoded by the gbs1783 gene, since this gene can complement an Escherichia coli ispB mutant defective for isoprenoids chain synthesis. In the gut or vaginal microbiote, where interspecies metabolite exchanges occur, this partial DMK biosynthetic pathway can be important for GBS respiration and survival in different niches.

Topics: Benzoquinones; Biosynthetic Pathways; Heme; Metabolic Networks and Pathways; Naphthols; Streptococcus agalactiae; Vitamin K 2

Escherichia coli is used as a model organism for elucidation of menaquinone biosynthesis, for which a hydrolytic step from 1,4-dihydroxy-2-naphthoyl-coenzyme A (DHNA-CoA) to 1,4-dihydroxy-2-naphthoate is still unaccounted for. Recently, a hotdog fold thioesterase has been shown to catalyze this conversion in phylloquinone biosynthesis, suggesting that its closest homolog, YbgC in Escherichia coli, may be the DHNA-CoA thioesterase in menaquinone biosynthesis. However, this possibility is excluded by the involvement of YbgC in the Tol-Pal system and its complete lack of hydrolytic activity toward DHNA-CoA. To identify the hydrolytic enzyme, we have performed an activity-based screen of all nine Escherichia coli hotdog fold thioesterases and found that YdiI possesses a high level of hydrolytic activity toward DHNA-CoA, with high substrate specificity, and that another thioesterase, EntH, from siderophore biosynthesis exhibits a moderate, much lower DHNA-CoA thioesterase activity. Deletion of the ydiI gene from the bacterial genome results in a significant decrease in menaquinone production, which is little affected in ΔybgC and ΔentH mutants. These results support the notion that YdiI is the DHNA-CoA thioesterase involved in the biosynthesis of menaquinone in the model bacterium.

Topics: Biosynthetic Pathways; Escherichia coli; Escherichia coli Proteins; Gene Deletion; Naphthols; Substrate Specificity; Thiolester Hydrolases; Vitamin K 2

In this study, we investigated the role of menaquinone biosynthesis genes in selenate reduction by Enterobacter cloacae SLD1a-1 and Escherichia coli K12. A mini-Tn5 transposon mutant of E. cloacae SLD1a-1, designated as 4E6, was isolated that had lost the ability to reduce Se(VI) to Se(0). Genetic analysis of mutant strain 4E6 showed that the transposon was inserted within a menD gene among a menFDHBCE gene cluster that encodes for proteins required for menaquinone biosynthesis. A group of E. coli K12 strains with single mutations in the menF, menD, menC and menE genes were tested for loss of selenate reduction activity. The results showed that E. coli K12 carrying a deletion of either the menD, menC or menE gene was unable to reduce selenate. Complementation using wild-type sequences of the E. cloacae SLD1a-1 menFDHBCE sequence successfully restored the selenate reduction activity in mutant strain 4E6, and E. coli K12 menD and menE mutants. Selenate reduction activity in 4E6 was also restored by chemical complementation using the menaquinone precursor compound 1,4-dihydroxy-2-nathphoic acid. The results of this work suggest that menaquinones are an important source of electrons for the selenate reductase, and are required for selenate reduction activity in E. cloacae SLD1a-1 and E. coli K12.

Topics: Carbon-Carbon Lyases; Coenzyme A Ligases; DNA Transposable Elements; DNA, Bacterial; Enterobacter cloacae; Escherichia coli K12; Escherichia coli Proteins; Gene Deletion; Genetic Complementation Test; Molecular Sequence Data; Mutagenesis, Insertional; Naphthols; Oxidation-Reduction; Pyruvate Oxidase; Selenic Acid; Selenium Compounds; Sequence Analysis, DNA; Vitamin K 2

The production of 1,4-dihydroxy-2-naphthoic acid (DHNA) was investigated using a fed-batch culture of Propionibacterium freudenreichii ET-3. DHNA is a precursor of menaquinone (MK) and is transformed to MK by combination with an isoprenoid unit. We found that ET-3 stopped MK production and increased DHNA production in an anaerobic fed-batch culture by maintaining the lactose concentration at approximately zero. The maximum DHNA concentration observed in the anaerobic fed-batch culture was markedly higher than the maximum DHNA concentration observed in an anaerobic batch culture. Moreover, MK or DHNA production was affected by the lactose feeding rate; this suggests that lactose metabolism participates in the syntheses of these products. On the other hand, accumulation of propionate was found to inhibit DHNA production in the fed-batch culture. Based on the fact that ET-3 increases DHNA production in an aerobic culture by consuming propionate, we carried out a cultivation experiment in which an anaerobic fed-batch culture was switched to an anaerobic batch culture and found that the DHNA production was increased to a greater extent than the DHNA production in an anaerobic fed-batch culture. These results suggest that DHNA production by ET-3 is markedly influenced by carbon source limitation and the oxygen supply.

Topics: Anaerobiosis; Carbon; Enzyme Inhibitors; Fermentation; Lactose; Naphthols; Oxygen; Propionates; Propionibacterium; Vitamin K 2

This is the first report on the production of both 1,4-dihydroxy-2-naphthoic acid (DHNA) and menaquinone by Propionibacterium freudenreichii ET-3. DHNA can be a stimulator of bifidogenic growth, and menaquinone has important roles in blood coagulation and bone metabolism. During anaerobic culture, DHNA and menaquinone concentrations reached 0.18 mM and 0.12 mM, respectively. The molar ratio between these products was approximately 3:2, which was not affected by culture pH and temperature over the ranges of 6.0-7.0 and 31-35 degrees C, respectively. As for organic acid, propionate and acetate accumulated at concentrations of 0.3 M and 0.15 M, respectively, and the propionate accumulation particularly inhibited further production of DHNA. To improve DHNA production, we switched from anaerobic condition to aerobic condition during the culture when lactose was depleted. DHNA concentration continued to increase even after lactose exhaustion, reaching 0.24 mM. In contrast to DHNA production, menaquinone production stopped after the switch to aerobic condition. The total molar production of DHNA and menaquinone was 0.3 mM irrespective of aerobic culture and anaerobic-aerobic switching culture. Therefore, the anaerobic-aerobic switching culture could increase the production ratio of DHNA to menaquinone. The DHNA concentration obtained from the anaerobic-aerobic switching culture was 1.3-fold higher than that in the anaerobic culture, because P. freudenreichii ET-3 utilized propionate accumulated in the medium via the reversed methylmalonyl CoA pathway under aerobic condition. The culture method proposed in this study could be applicable to industrial-scale fermentation using 1000 l of media, by which 0.23 mM DHNA was produced.

Topics: Aerobiosis; Cell Culture Techniques; Naphthols; Oxygen; Propionibacterium; Species Specificity; Vitamin K 2

The secondary electron acceptor of photosystem (PS) I in the cyanobacterium Gloeobacter violaceus PCC 7421 was identified as menaquinone-4 (MQ-4) by comparing high performance liquid chromatograms and absorption spectra with an authentic compound. The MQ-4 content was estimated to be two molecules per one molecule of chlorophyll (Chl) a', a constituent of P700. Comparative genomic analyses showed that six of eight men genes, encoding phylloquinone/MQ biosynthetic enzymes, are missing from the G. violaceus genome. Since G. violaceus clearly synthesizes MQ-4, the combined results indicate that this cyanobacterium must have a novel pathway for the synthesis of 1,4-dihydroxy-2-naphthoic acid.

Topics: Chlorophyll; Cyanobacteria; Genome, Bacterial; Naphthols; Photosystem I Protein Complex; Vitamin K 1; Vitamin K 2

Transformation of carbon tetrachloride (CT) by Shewanella oneidensis MR-1 has been proposed to involve the anaerobic respiratory-chain component menaquinone. To investigate this hypothesis a series of menaquinone mutants were constructed. The menF mutant is blocked at the start of the menaquinone biosynthetic pathway. The menB, menA and menG mutants are all blocked towards the end of the pathway, being unable to produce 1,4-dihydroxy-2-naphthoic acid (DHNA), demethyl-menaquinone and menaquinone, respectively. Aerobically grown mutants unable to produce the menaquinone precursor DHNA (menF and menB mutants) showed a distinctly different CT transformation profile than mutants able to produce DHNA but unable to produce menaquinone (menA and menG mutants). While DHNA did not reduce CT in an abiotic assay, the addition of DHNA to the menF and menB mutants restored normal CT transformation activity. We conclude that a derivative of DHNA, that is distinct from menaquinone, is involved in the reduction of CT by aerobically grown S. oneidensis MR-1. When cells were grown anaerobically with trimethylamine-N-oxide as the terminal electron acceptor, all the menaquinone mutants showed wild-type levels of CT reduction. We conclude that S. oneidensis MR-1 produces two different factors capable of dehalogenating CT. The factor produced under anaerobic growth conditions is not a product of the menaquinone biosynthetic pathway.

Topics: Aerobiosis; Alkyl and Aryl Transferases; Anaerobiosis; Biotransformation; Carbon Tetrachloride; Genes, Bacterial; Kinetics; Methylamines; Mutation; Naphthols; Oxidation-Reduction; Shewanella; Vitamin K 2

1,4-Dihydroxy-2-naphthoate:polyprenyltransferase was detected in the membrane fraction from Micrococcus luteus. The specificity of the enzyme ws so tolerant as regards the prenyl-donating substrate that prenyl pyrophosphates ranging in chain length from C15 to C45 were active as substrates. The monophosphate esters were also active, though the reactivities were much lower than those of the corresponding pyrophosphates. The enzyme showed rigorous specificity with respect to the aromatic substrate. Neither 1,4-dihydroxynaphthalene nor its 2-methyl derivative was active at all. 1,4-Dihydroxy-3-methyl-2-naphthoate could be prenylated to afford menaquinone, but the reactivity was much less than that of its demethyl derivative. These results support the view that menaquinone biosynthesis involves the prenylation of 1,4-dihydroxy-2-naphthoate prior to decarboxylation or methylation.

Topics: Alkyl and Aryl Transferases; Cell Membrane; Farnesol; Micrococcus; Naphthols; Polyisoprenyl Phosphates; Sesquiterpenes; Substrate Specificity; Transferases; Vitamin K; Vitamin K 2