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Collected data have been analyzed using DynaPro dynamic light scattering instrument software to calculate the molecular mass. Exopolyphosphatase assays The exopolyphosphatase activities of Rv, EC-PPX and EC-GPP had been determined making use of continuous spectrophotometric assays, quantifying phosphate release making use of the EnzChek phosphate assay kit based on the manufacturer's protocol; analogous for the method reported by Lindner et al.. Unless otherwise stated, assays have been performed in -well plates at uC, in ml of mM HEPES pH ., mM MnCl, mM KCl, containing EC-PPX, EC-PPX or Rv protein, polyphosphate on the stated chain length; quantifying modifications in the absorbance at nm working with a Spectra Max plate reader. Inorganic polyphosphate samples with average chain lengths of P, P and P had been supplied by Dr. T. Shiba. Vmax and Km values have been determined by fitting data towards the Michaelis-Menten equation utilizing Origin .. Experiments have been performed in quadruplicate, as well as the imply values typical deviation are reported. Protein expression and purification E. coli BL cells transformed using the appropriate expression plasmid, had been cultured at uC in Luria Bertani medium until the OD reached ca. Protein expression was induced by adding to a final concentration of . mM, then cells were cultured at area temperature for hours. Cells pellet were collected and lysed by sonication in either `Nibinding buffer' for pETa constructs; or `maltose-binding buffer' for pMAL-C constructs, containing Lenvatinib Results protease inhibitors. Lysates had been centrifuged, then supernatants had been filtered before purification onto a ml HiTrap Chelating HP column constructs) or ml MBPTrap HP. Recombinant E. coli GPP and PPX proteins had been eluted with mM Tris-HCl Analysis of poly-P digestion making use of polyacrylamide gel electrophoresis Reaction mixtures containing E. coli GPP, Rv, Rv protein and . mM poly-P in mM HEPES pH ., mM KCl, mM MnCl, have been incubated at uC for hours. Adverse controls have been analogously incubated: i) no added MnCl, ii) no protein, iii) MBD protein. Loading buffer was added, and reaction mixtures have been analyzed on TBE-polyacrylamide gels and stained with toluidine blue as Biochemical Activities of Rv and Rv previously described. Gels were visualized and bands quantified employing a ChemiDoc XRS molecular imaging technique with Quantity A single v.. application Complementation assays for determining exopolyphosphatase and pppGpp hydrolase activities Preparation of cell lysates. Stationary phase cultures of E. coli MG and CF in ml LB medium were expanded into ml LB medium and incubated at uC till the early stationary phase. Mycobacterium smegmatis mc was analogously cultured in Brain Heart Infusion medium containing . Tween at uC. Cells have been harvested by centrifugation, washed and resuspended in mM Tris-HCl + sucrose. Lysozyme was added towards the resuspended E. coli MG and CF cell suspensions; which have been frozen, thawed, incubated at uC, then chilled on ice. Cells suspensions were lysed and homogenized by sonication, before centrifugation. Supernatants have been decanted, and protein concentrations had been determined by Bradford assay, just before freezing aliquots in liquid nitrogen, for storage at uC. pppGpp hydrolysis assays. Thawed cell lysates have been incubated with . mM pppGpp in mM TrisHCl, . mM DTT, mM MnCl at uC for hours. Analogous experiments have been performed together with the addition of mg of MTB-PPX, Rv, E. coli GPP, E.