Ampicillin

Ampicillin and isopropyl-β-D-1-tiogalactopyranoside were from Apollo Scientific (Stockport, UK). Imidazole, kanamycin, TSP ((trimethylsilyl)-2,2,3,3-tetradeuteropropionic acid), Trizma base, and His-Select HF nickel resin were from Sigma-Aldrich (Madrid, Spain). Triton X-100 and protein marker (PAGEmark Tricolor) were from VWR (Barcelona, Spain). Amicon centrifugal devices with a cut-off molecular weight of 30 or 50 kDa were from Millipore (Barcelona, Spain). The rest of the materials were of analytical grade. Water was deionized and purified on a Millipore system.

Plasmids pCri9a-KL123 and pCri9a-KL23 were transformed into competent Lemo21 (DE3) Escherichia coli cells (New England Biolabs) and plated on Luria-Bertani (LB) plates. Fifty millilitres of lysogeny broth was inoculated with a single bacterial colony and incubated overnight at 37 °C under stirring at 220 rpm. Five millilitres of this preinoculum was used to inoculate 500 mL of lysogeny broth, and cells were left to grow at 37 °C until OD₆₀₀ ≈ 0.7. Subsequently, cultures were cooled to 20 °C and protein expression was induced with 0.4 mM isopropyl-β-D-1-thiogalactopyranoside (IPTG; Duchefa) for 18–20 h. LB plates and lysogeny broth were supplemented with 50 μg/mL kanamycin (Fisher Bioreagents) and 34 μg/mL chloramphenicol (Fluka).
For the expression of MMP-14 catalytic domain (CD), E. coli BL21 (DE3) cells (Sigma) were transformed with plasmid pET3a-MT1∆C. One hundred millilitres of lysogeny broth was inoculated with a single colony and incubated overnight at 28 °C under stirring at 200 rpm. Ten millilitres of this preinoculum was used to inoculate 500 mL of lysogeny broth, and cells were left to grow at 37 °C until OD₆₀₀ ≈ 0.6. Cells were then induced with 0.5 mM IPTG and kept for 5 h at 37 °C. LB plates and lysogeny broth were supplemented with 100 μg/mL ampicillin (Apollo Scientific).

Ampicillin and isopropyl-β-D-1-thiogalactopyranoside were obtained from Apollo Scientific (Stockport, UK). Imidazole, Trizma base, DNAse, SIGMAFAST protease tablets and His-Select HF nickel resin were from Sigma-Aldrich (Madrid, Spain). Ultra-pure GdmCl and urea were from Pierce (USA). Amicon centrifugal devices with a cut-off molecular weight of 10 kDa were from Millipore (Barcelona, Spain). The rest of the used materials were of analytical grade. Water was de-ionised and purified on a Millipore system.

Isopropyl-β-d-1-tiogalactopyranoside and ampicillin were obtained from Apollo Scientific (Stockport, UK). Imidazole, kanamycin, Trizma base, and His-Select HF nickel resin were from Sigma-Aldrich (Madrid, Spain). Protein marker (PAGEmark Tricolor) and Triton X-100 were from VWR (Barcelona, Spain). Amicon centrifugal devices were from Millipore (Barcelona, Spain), and they had a cut-off molecular weight of 30 or 50 kDa. The rest of the materials were of analytical grade. Water was deionized and purified on a Millipore system.

Bdellovibrio bacteriovorus strain HD100^T was used throughout and was maintained on Ca/HEPES buffer with E. coli S17-1 as prey as described previously11 (link)30 (link). Prey strains E. coli S17-1, E. coli 083:H1, Acinetobacter baumannii, Proteus mirabilis and Pseudomonas putida were grown in YT broth for 16 hours at 37 °C with shaking at 200 rpm. Where appropriate, Ampicillin (Apollo Scientific) was used at 50 μg ml⁻¹ and IPTG (isopropyl-β-D-1-thiogalactopyranoside) used for induction of fluorescent protein expression in E. coli at 200 μg ml⁻¹.

Ampicillin and isopropyl-β-D-1-tiogalactopyranoside were obtained from Apollo Scientific (Stockport, United Kingdom). Imidazole, bovine serum albumin (BSA), Trizma base, TSP ((trimethylsilyl)-2,2,3,3-tetradeuteropropionic acid), SIGMA-FAST-EDTA-free Protease inhibitor, 2,2,2-trifluorethanol (TFE), the ¹⁵NH₄Cl salt and His-Select HF nickel resin were from Sigma-Aldrich (Madrid, Spain). Triton X-100, the paramagnetic probe S-(1-oxyl.2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-3-yl) methyl methane sulfonothioate (MTSL), ultra-pure urea, ultra-pure guanidinium hydrochloride (GdmCl), polytetrafluoroethylene (PTFE) filters with a size of 0.22 μm, and protein marker (PAGEmark Tricolor) were from VWR (Barcelona, Spain). Dextran-40, Ficoll-70 and PD-10 desalting-columns were acquired from GE Healthcare (Barcelona, Spain). Bio-Rad (Madrid, Spain) column sleeves were used for the Ni-immobility affinity column chromatography step. Amicon centrifugal devices with a cut-off molecular weight of 3 kDa were from Millipore (Barcelona, Spain). The rest of the materials were of analytical grade. Water was deionized and purified on a Millipore system.