title: New gene responsible for para-aminobenzoate biosynthesis.
abstract: 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.
authors: Faculty of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo 060-8628, Japan.
authors: Yasuharu
authors: Y
authors: Satoh
authors: Kyowa Hakko Bio Co. Ltd., 1-6-1, Ohtemachi, Chiyoda-ku, Tokyo 100-8185, Japan.
authors: Masahiro
authors: M
authors: Kuratsu
authors: Faculty of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo 060-8628, Japan.
authors: Daiki
authors: D
authors: Kobayashi
authors: Faculty of Engineering, Hokkaido University, N13-W8, Kita-ku, Sapporo 060-8628, Japan. Electronic address: dairi@eng.hokudai.ac.jp.
authors: Tohru
authors: T
authors: Dairi
mesh_terms: D019755:Carbon-Carbon Lyases / Q000235:genetics; D002692:Chlamydia trachomatis / Q000235:genetics*; D003001:Cloning, Molecular; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics; D019143:Evolution, Molecular; D005492:Folic Acid / Q000096:biosynthesis / Q000378:metabolism; D017353:Gene Deletion; D005798:Genes, Bacterial / Q000235:genetics*; D005816:Genetic Complementation Test; D043370:Nitrosomonas europaea / Q000235:genetics*; D012765:Shikimic Acid / Q000378:metabolism; D013379:Substrate Specificity; D000637:Transaminases / Q000235:genetics / Q000378:metabolism; D014169:Transformation, Bacterial; D062366:para-Aminobenzoates / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D062366:para-Aminobenzoates; D012765:Shikimic Acid; D005492:Folic Acid; D000637:Transaminases; C000707653:aminodeoxychorismate synthase protein, E coli; C066599:aminodeoxychorismate synthase; D019755:Carbon-Carbon Lyases
keywords: Chlamydia trachomatis; Folate; Lactobacillus fermentum; Nitrosomonas europaea; para-Aminobenzoate