Bharati Mitra

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The first Zn(II)-translocating P-type ATPase has been identified as the product of o732, a potential gene identified in the sequencing of the Escherichia coli genome. This gene, termed zntA, was disrupted by insertion of a kanamycin gene through homologous recombination. The mutant strain exhibited hypersensitivity to zinc and cadmium salts but not salts of(More)
ZntA, a soft metal-translocating P1-type ATPase from Escherichia coli, confers resistance to Pb(II), Cd(II), and Zn(II). ZntA was expressed as a histidyl-tagged protein, solubilized from membranes with Triton X-100, and purified to homogeneity. The soft metal-dependent ATP hydrolysis activity of purified ZntA was characterized. The activity was specific for(More)
The copA gene product, a putative copper-translocating P-type ATPase, has been shown to be involved in copper resistance in Escherichia coli. The copA gene was disrupted by insertion of a kanamycin gene through homologous recombination. The mutant strain was more sensitive to copper salts but not to salts of other metals, suggesting a role in copper(More)
The cad operon of Staphylococcus aureus plasmid pI258, which confers cadmium resistance, encodes a transcriptional regulator, CadC, and CadA, an ATP-coupled Cd(II) pump that is a member of the superfamily of cation-translocating P-type ATPases. The Escherichia coli homologue of CadA, termed ZntA, is a Zn(II)/Cd(II) pump. The results described in this paper(More)
Soft metal-translocating P1-type ATPases have a distinctive amino-terminal domain that contains one to six copies of the conserved metal-binding motif, GXXCXXC. ZntA from Escherichia coli, a Pb(II)-, Zn(II)-, and Cd(II)-transporting ATPase, has an approximately 120 residue amino-terminal domain with one copy of the GXXCXXC motif as well as four additional(More)
In a search for genes responsible for the accumulation of antimonite in Escherichia coli, TnphoA was used to create a pool of random insertional mutants, from which one antimonite-resistant mutant was isolated. Sequence analysis showed that the TnphoA insertion was located in the glpF gene, coding for the glycerol facilitator GlpF. The mutant was shown to(More)
A novel serine protease inhibitor (AmPI) was purified from larval hemolymph of tasar silkworm, Antheraea mylitta by two-step process of trypsin-affinity and gel-filtration (FPLC) chromatography. AmPI was active against larval midgut and commercial bovine trypsin and chymotrypsin. The extent of purification was determined by SDS and Native PAGE. The protease(More)
(S)-Mandelate dehydrogenase from Pseudomonas putida is a member of a FMN-dependent enzyme family that oxidizes (S)-alpha-hydroxyacids to alpha-ketoacids. The reductive half-reaction consists of the steps involved in substrate oxidation and FMN reduction. In this study, we investigated the mechanism of this half-reaction in detail. At low temperatures, a(More)
ZntA from Escherichia coli is a P-type ATPase that confers resistance to Pb(II), Zn(II), and Cd(II) in vivo. We had previously shown that purified ZntA shows ATP hydrolysis activity with the metal ions Pb(II), Zn(II), and Cd(II). In this study, we utilized the acylphosphate formation activity of ZntA to further investigate the substrate specificity of ZntA.(More)
ATP7B, the Wilson disease-associated Cu(I)-transporter, and ZntA from Escherichia coli are soft metal P1-type ATPases with mutually exclusive metal ion substrates. P1-type ATPases have a distinctive amino-terminal domain containing the conserved metal-binding motif GXXCXXC. ZntA has one copy of this motif while ATP7B has six copies. The effect of(More)