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.

• A new bacterial hydrolase specific for the compatible solutes alpha-D-mannopyranosyl-(1→2)-D-glycerate and alpha-D-glucopyranosyl-(1→2)-D-glycerate.

  Alarico S., Empadinhas N., da Costa M.S.

  The accumulation patterns and biosynthesis of compatible solutes in hyper/thermophiles have been extensively studied. However, there is little information available on their hydrolysis, leading us to search for enzymes for this activity. From the analysis of the genomes of several microorganisms k ... >> More

  The accumulation patterns and biosynthesis of compatible solutes in hyper/thermophiles have been extensively studied. However, there is little information available on their hydrolysis, leading us to search for enzymes for this activity. From the analysis of the genomes of several microorganisms known to accumulate α-D-mannopyranosyl-(1→2)-D-glycerate (mannosylglycerate, MG) or α-D-glucopyranosyl-(1→2)-D-glycerate (glucosylglycerate, GG) we were able to identify a likely candidate gene for the hydrolysis of these molecules. The Thermus thermophilus HB27 homologue encoded a putative enzyme with motifs of the GH63 and GH37 families of glycoside hydrolases. We expressed the gene from this thermophilic bacterium and from Rubrobacter radiotolerans, and confirmed that the recombinant enzymes, here designated mannosylglycerate hydrolase (MgH), specifically hydrolysed MG (or GG) to mannose (or glucose) and glycerate. Both enzymes were highly stable and maximally active at temperatures close to each organisms' optimal growth temperatures (half-lives of 15.4 ± 0.5 h at 55 °C and 16.1 ± 0.4 h at 70 °C) but at low pH (4.0-4.5). Cations were not required for their activity and each enzyme exhibited Michaelis-Menten kinetics at 50 °C and 70 °C, respectively, with comparable catalytic efficiencies towards MG and GG. Herein, we purified and characterized a novel and highly specific MG- and GG-hydrolyzing enzyme that represent an attractive tool for development of enzymatic assays for quantification of these solutes, which seem to be more prevalent in microorganisms than initially suspected. << Less

  Enzyme Microb Technol 52:77-83(2013) [PubMed] [EuropePMC]