Physiological role of FolD (methylenetetrahydrofolate dehydrogenase), FchA (methenyltetrahydrofolate cyclohydrolase) and Fhs (formyltetrahydrofolate synthetase) from Clostridium perfringens in a heterologous model of Escherichia coli.
Microbiology (Reading)
; 162(1): 145-155, 2016 Jan.
Article
em En
| MEDLINE
| ID: mdl-26531681
ABSTRACT
Most organisms possess bifunctional FolD [5,10-methylenetetrahydrofolate (5,10-CH2-THF) dehydrogenase-cyclohydrolase] to generate NADPH and 10-formyltetrahdrofolate (10-CHO-THF) required in various metabolic steps. In addition, some organisms including Clostridium perfringens possess another protein, Fhs (formyltetrahydrofolate synthetase), to synthesize 10-CHO-THF. Here, we show that unlike the bifunctional FolD of Escherichia coli (EcoFolD), and contrary to its annotated bifunctional nature, C. perfringens FolD (CpeFolD) is a monofunctional 5,10-CH2-THF dehydrogenase. The dehydrogenase activity of CpeFolD is about five times more efficient than that of EcoFolD. The 5,10-methenyltetrahydrofolate (5,10-CH+-THF) cyclohydrolase activity in C. perfringens is provided by another protein, FchA (5,10-CH+-THF cyclohydrolase), whose cyclohydrolase activity is â¼ 10 times more efficient than that of EcoFolD. Kinetic parameters for CpeFhs were also determined for utilization of all of its substrates. Both CpeFolD and CpeFchA are required to substitute for the single bifunctional FolD in E. coli. The simultaneous presence of CpeFolD and CpeFchA is also necessary to rescue an E. coli folD deletion strain (harbouring CpeFhs support) for its formate and glycine auxotrophies, and to alleviate its susceptibility to trimethoprim (an antifolate drug) or UV light. The presence of the three clostridial proteins (FolD, FchA and Fhs) is required to maintain folate homeostasis in the cell.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Clostridium perfringens
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Meteniltetra-Hidrofolato Cicloidrolase
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Escherichia coli
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Formiato-Tetra-Hidrofolato Ligase
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Metilenotetra-Hidrofolato Desidrogenase (NADP)
Idioma:
En
Revista:
Microbiology (Reading)
Assunto da revista:
MICROBIOLOGIA
Ano de publicação:
2016
Tipo de documento:
Article
País de afiliação:
Índia