Publications

• The plant Selaginella moellendorffii possesses enzymes for synthesis and hydrolysis of the compatible solutes mannosylglycerate and glucosylglycerate.

  Nobre A., Empadinhas N., Nobre M.F., Lourenco E.C., Maycock C., Ventura M.R., Mingote A., da Costa M.S.

  A mannosylglycerate synthase (MgS) gene detected in the genome of Selaginella moellendorffii was expressed in E. coli and the recombinant enzyme was purified and characterized. A remarkable and unprecedented feature of this enzyme was the ability to efficiently synthesize mannosylglycerate (MG) an ... >> More

  A mannosylglycerate synthase (MgS) gene detected in the genome of Selaginella moellendorffii was expressed in E. coli and the recombinant enzyme was purified and characterized. A remarkable and unprecedented feature of this enzyme was the ability to efficiently synthesize mannosylglycerate (MG) and glucosylglycerate (GG) alike, with maximal activity at 50 °C, pH 8.0 and with Mg(2+) as reaction enhancer. We have also identified a novel glycoside hydrolase gene in this plant's genome, which was functionally confirmed to be highly specific for the hydrolysis of MG and GG and named MG hydrolase (MgH), due to its homology with bacterial MgHs. The recombinant enzyme was maximally active at 40 °C and at pH 6.0-6.5. The activity was independent of cations, but Mn(2+) was a strong stimulator. Regardless of these efficient enzymatic resources we could not detect MG or GG in S. moellendorffii or in the extracts of five additional Selaginella species. Herein, we describe the properties of the first eukaryotic enzymes for the synthesis and hydrolysis of the compatible solutes, MG and GG. << Less

  Planta 237:891-901(2013) [PubMed] [EuropePMC]

  This publication is cited by 3 other entries.

• Production, crystallization and structure determination of a mycobacterial glucosylglycerate hydrolase.

  Cereija T.B., Alarico S., Empadinhas N., Pereira P.J.B.

  Glucosylglycerate hydrolase is highly conserved among rapidly growing mycobacteria and has been found to be involved in recovery from nitrogen starvation by promoting the rapid mobilization of the glucosylglycerate that accumulates under these conditions. Here, the production, crystallization and ... >> More

  Glucosylglycerate hydrolase is highly conserved among rapidly growing mycobacteria and has been found to be involved in recovery from nitrogen starvation by promoting the rapid mobilization of the glucosylglycerate that accumulates under these conditions. Here, the production, crystallization and structure determination of glucosylglycerate hydrolase from Mycobacterium hassiacum using two-wavelength anomalous diffraction of selenomethionine-substituted crystals are described. The monoclinic (space group P2₁) crystals diffracted to ∼2.0 Å resolution at a synchrotron-radiation source and contained four molecules in the asymmetric unit, corresponding to a Matthews coefficient of 3.07 ų Da^-1 and a solvent content of 59.9%. The quality of the experimental phases allowed the automated building of 1677 of the 1792 residues in the asymmetric unit. << Less

  Acta Crystallogr. F Struct. Biol. Commun. 73:536-540(2017) [PubMed] [EuropePMC]

• Mycobacterium hassiacum recovers from nitrogen starvation with up-regulation of a novel glucosylglycerate hydrolase and depletion of the accumulated glucosylglycerate.

  Alarico S., Costa M., Sousa M.S., Maranha A., Lourenco E.C., Faria T.Q., Ventura M.R., Empadinhas N.

  Some microorganisms accumulate glucosylglycerate (GG) during growth under nitrogen deprivation. However, the molecular mechanisms underlying the role of GG and the regulation of its levels in the nitrogen stress response are elusive. Since GG is required for biosynthesis of mycobacterial methylglu ... >> More

  Some microorganisms accumulate glucosylglycerate (GG) during growth under nitrogen deprivation. However, the molecular mechanisms underlying the role of GG and the regulation of its levels in the nitrogen stress response are elusive. Since GG is required for biosynthesis of mycobacterial methylglucose lipopolysaccharides (MGLP) we examined the molecular mechanisms linking replenishment of assimilable nitrogen to nitrogen-starved M. hassiacum with depletion of GG accumulated during nitrogen deficiency. To probe the involvement of a newly identified glycoside hydrolase in GG depletion, we produced the mycobacterial enzyme recombinantly and confirmed the specific hydrolysis of GG (GG hydrolase, GgH) in vitro. We have also observed a pronounced up-regulation of GgH mRNA in response to the nitrogen shock, which positively correlates with GG depletion in vivo and growth stimulation, implicating GgH in the recovery process. Since GgH orthologs seem to be absent from most slowly-growing mycobacteria including M. tuberculosis, the disclosure of the GgH function allows reconfiguration of the MGLP pathway in rapidly-growing species and accommodation of this possible regulatory step. This new link between GG metabolism, MGLP biosynthesis and recovery from nitrogen stress furthers our knowledge on the mycobacterial strategies to endure a frequent stress faced in some environments and during long-term infection. << Less

  Sci. Rep. 4:6766-6766(2014) [PubMed] [EuropePMC]