Utilisation of 10-formyldihydrofolate as substrate by dihydrofolate reductase (DHFR) and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) tranformylase/IMP cyclohydrolase (PurH) in <i>Escherichia coli</i>.

Sah, Shivjee; Shah, Riyaz Ahmad; Govindan, Ashwin; Varada, Rajagopal; Rex, Kervin; Varshney, Umesh

Utilisation of 10-formyldihydrofolate as substrate by dihydrofolate reductase (DHFR) and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) tranformylase/IMP cyclohydrolase (PurH) in Escherichia coli.

Sah, Shivjee; Shah, Riyaz Ahmad; Govindan, Ashwin; Varada, Rajagopal; Rex, Kervin; Varshney, Umesh.

Afiliación

Sah S; Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
Shah RA; Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
Govindan A; Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
Varada R; Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
Rex K; Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
Varshney U; Jawaharlal Nehru Centre for Advanced Scientific Research, Bangalore 560064, India.

Microbiology (Reading) ; 164(7): 982-991, 2018 07.

Article en En | MEDLINE | ID: mdl-29799386

RESUMEN

Dihydrofolate reductase (DHFR) and 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) transformylase/IMP cyclohydrolase (PurH) play key roles in maintaining folate pools in cells, and are targets of antimicrobial and anticancer drugs. While the activities of bacterial DHFR and PurH on their classical substrates (DHF and 10-CHO-THF, respectively) are known, their activities and kinetic properties of utilisation of 10-CHO-DHF are unknown. We have determined the kinetic properties (kcat/Km) of conversion of 10-CHO-DHF to 10-CHO-THF by DHFR, and to DHF by PurH. We show that DHFR utilises 10-CHO-DHF about one third as efficiently as it utilises DHF. The 10-CHO-DHF is also utilised (as a formyl group donor) by PurH albeit slightly less efficiently than 10-CHO-THF. The utilisation of 10-CHO-DHF by DHFR is ~50 fold more efficient than its utilisation by PurH. A folate deficient Escherichia coli (∆pabA) grows well when supplemented with adenine, glycine, thymine and methionine, the metabolites that arise from the one-carbon metabolic pathway. Notably, when the ∆pabA strain harboured a folate transporter, it grew in the presence of 10-CHO-DHF alone, suggesting that it (10-CHO-DHF) can enter one-carbon metabolic pathway to provide the required metabolites. Thus, our studies reveal that both DHFR and PurH could utilise 10-CHO-DHF for folate homeostasis in E. coli.

Asunto(s)

Escherichia coli/metabolismo; Ácido Fólico/análogos & derivados; Nucleótido Desaminasas/metabolismo; Fosforribosilaminoimidazolcarboxamida-Formiltransferasa/metabolismo; Tetrahidrofolato Deshidrogenasa/metabolismo; Ácido 4-Aminobenzoico; Clonación Molecular; Escherichia coli/genética; Escherichia coli/crecimiento & desarrollo; Ácido Fólico/metabolismo; Deficiencia de Ácido Fólico/genética; Homeostasis; Cinética; Redes y Vías Metabólicas; Nucleótido Desaminasas/genética; Fosforribosilaminoimidazolcarboxamida-Formiltransferasa/genética; Tetrahidrofolato Deshidrogenasa/genética

Palabras clave

10-CHO-DHF; 10-CHO-THF; DHF; DHFR; PurH; THF; folate pathway; one-carbon metabolic pathway

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Texto completo: 1 Colección: 01-internacional Base de datos: MEDLINE Asunto principal: Tetrahidrofolato Deshidrogenasa / Escherichia coli / Fosforribosilaminoimidazolcarboxamida-Formiltransferasa / Ácido Fólico / Nucleótido Desaminasas Idioma: En Revista: Microbiology (Reading) Asunto de la revista: MICROBIOLOGIA Año: 2018 Tipo del documento: Article País de afiliación: India Pais de publicación: Reino Unido

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