RESUMO
Folate is an essential cofactor in all living cells for one-carbon transfer reactions. para-Aminobenzoate (pABA), a building block of folate, is usually derived from chorismate in the shikimate pathway by reactions of aminodeoxychorismate synthase (PabA and -B) and 4-amino-4-deoxychorismate lyase (PabC). We previously suggested that an alternative pathway for pABA biosynthesis would operate in some microorganisms such as Lactobacillus fermentum and Nitrosomonas europaea since these bacteria showed a prototrophic phenotype to pABA despite the fact that there are no orthologs of pabA, -B, and -C in their genome databases. In this study, a gene of unknown function, NE1434, was obtained from N. europaea by shotgun cloning using a pABA-auxotrophic Escherichia coli mutant (ΔpabABC) as a host. A tracer experiment using [U-(13)C6]glucose suggested that pABA was de novo synthesized in the transformant. An E. coli ΔpabABCΔaroB mutant carrying the NE1434 gene exhibited a prototrophic phenotype to pABA, suggesting that compounds in the shikimate pathway including chorismate were not utilized as substrates by NE1434. Moreover, the CT610 gene, an ortholog of NE1434 located in the folate biosynthetic gene cluster in Chlamydia trachomatis, also complemented pABA-auxotrophic E. coli mutants. Taken together, these results suggest that NE1434 and CT610 participate in pABA biosynthesis.
Assuntos
Chlamydia trachomatis/genética , Genes Bacterianos/genética , Nitrosomonas europaea/genética , para-Aminobenzoatos/metabolismo , Carbono-Carbono Liases/genética , Clonagem Molecular , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Evolução Molecular , Ácido Fólico/biossíntese , Ácido Fólico/metabolismo , Deleção de Genes , Teste de Complementação Genética , Ácido Chiquímico/metabolismo , Especificidade por Substrato , Transaminases/genética , Transaminases/metabolismo , Transformação BacterianaRESUMO
We recently demonstrated that the futalosine pathway was operating in some bacteria for the biosynthesis of menaquinone and that futalosine was converted into dehypoxanthinyl futalosine (DHFL) by an MqnB of Thermus thermophilus. In this study, we found that aminodeoxyfutalosine, which has adenine instead of hypoxanthine in futalosine, was directly converted into DHFL by an MqnB of Helicobacter pylori. Therefore, this step is potentially an attractive target for the development of specific anti-H. pylori drugs.
Assuntos
Bactérias/metabolismo , Helicobacter pylori/metabolismo , Hidrolases/metabolismo , Nucleosídeos/metabolismo , Adenina/química , Bactérias/enzimologia , Cromatografia Líquida de Alta Pressão , Helicobacter pylori/enzimologia , Helicobacter pylori/genética , Hidrolases/genética , Hipoxantina/metabolismo , Nucleosídeos/química , Thermus thermophilus/enzimologia , Thermus thermophilus/metabolismo , Vitamina K 2/metabolismoRESUMO
We performed analyses of the phenotypic and genotypic relationships focusing on biosyntheses of amino acids, purine/pyrimidines, and cofactors in three Lactobacillus strains. We found that Lactobacillus fermentum IFO 3956 perhaps synthesized para-aminobenzoate (PABA), an intermediate of folic acid biosynthesis, by an alternative pathway.
Assuntos
Lactobacillus/metabolismo , Ácido 4-Aminobenzoico/metabolismo , Aminoácidos/biossíntese , Genótipo , Lactobacillus/genética , Levilactobacillus brevis/genética , Levilactobacillus brevis/metabolismo , Limosilactobacillus fermentum/genética , Limosilactobacillus fermentum/metabolismo , Limosilactobacillus reuteri/genética , Limosilactobacillus reuteri/metabolismo , Redes e Vias Metabólicas , Fenótipo , Purinas/biossíntese , Pirimidinas/biossínteseRESUMO
In spite of their great importance for both applied and basic biology, studies on vesicular trafficking in filamentous fungi have been so far very limited. Here, we identified 21 genes, which might be a total set, encoding putative SNARE proteins that are key factors for vesicular trafficking, taking advantage of available whole genome sequence in the filamentous fungus Aspergillus oryzae. The subsequent systematic analysis to determine the localization of putative SNAREs using EGFP-fused chimeras revealed that most putative SNAREs show similar subcellular distribution to their counterparts in the budding yeast. However, there existed some characteristic features of SNAREs in A. oryzae, such as SNARE localization at/near the septum and the presence of apparently non-redundant plasma membrane Qa-SNAREs. Overall, this analysis allowed us to provide an overview of vesicular trafficking and organelle distribution in A. oryzae.
