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  • Cloning, purification and characterization of Geobacillus stearothermophilus V uroporphyrinogen-III C-methyltransferase: evaluation of its role in resistance to potassium tellurite in Escherichia coli.

Cloning, purification and characterization of Geobacillus stearothermophilus V uroporphyrinogen-III C-methyltransferase: evaluation of its role in resistance to potassium tellurite in Escherichia coli.

Research in microbiology (2009-01-22)
Manuel A Araya, Juan C Tantaleán, José M Pérez, Derie E Fuentes, Iván L Calderón, Claudia P Saavedra, Radhika Burra, Thomas G Chasteen, Claudio C Vásquez
ABSTRACT

The Geobacillus stearothermophilus V cobA gene encoding uroporphyrinogen-III C-methyltransferase (also referred to as SUMT) was cloned into Escherichia coli and the recombinant enzyme was overexpressed and purified to homogeneity. The enzyme binds S-adenosyl-L-methionine and catalyzes the production of III methyl uroporphyrinogen in vitro. E. coli cells expressing the G. stearothermophilus V cobA gene exhibited increased resistance to potassium tellurite and potassium tellurate. Site-directed mutagenesis of cobA abolished tellurite resistance of the mesophilic, heterologous host and SUMT activity in vitro. No methylated, volatile derivatives of tellurium were found in the headspace of tellurite-exposed cobA-expressing E. coli, suggesting that the role of SUMT methyltransferase in tellurite(ate) detoxification is not related to tellurium volatilization.

MATERIALS
Product Number
Brand
Product Description

Millipore
Potassium tellurite solution, 1% in H2O, suitable for microbiology