The cells were disrupted by sonication (8 × 10 s, 30 s breaks on ice, 50%) using the Misonix XL 2929 Sonicator Ultrasonic Processor with Cabinet (Misonix, Farmingdale, NY, USA). Unbroken cells were removed by centrifugation at 5,000 × g for 20 min. Supernatant was collected and transferred on the top of two-step sucrose gradient, containing 1 ml 55% (w/v) sucrose in 3 PRIMA-1MET datasheet mM EDTA (pH 8.0) on the bottom of an ultracentrifuge tube and 5 ml 17% (w/v) sucrose

on the top. The supernatant was subsequently centrifuged at 30,000 × g for 90 min to separate the membrane fraction from the cytosolic fraction. To membrane fractions equal volume of 3 mM EDTA (pH 8.0), and then 50% trichloroacetic acid (TCA) to the final concentration of 8% was added, and left overnight at 4°C. For protein precipitation, probes were centrifuged 60 min at 10,000 × g at 8°C, washed twice with acetone, each time spinning 15 min at 10,000 × g, air dried and final pellet selleck was resuspended in 200 μl loading buffer. The protein concentration in the final preparations was determined using the Bradford kit (Bio-Rad). Secreted and membrane proteins of the Rt24.2 and the Rt2472 were separated by find more SDS-PAGE with 12% acrylamide and visualized by staining with Coomassie brilliant blue G-250. Protein sequencing Membrane and extracellular protein fractions of Rt24.2 and Rt2472 separated by SDS-PAGE electrophoresis were transferred

onto polyvinylidene difluoride (PVDF) membrane (Sequi-Blot; Bio-Rad) using Interleukin-3 receptor the buffer

containing 2.2% 3-(cyclohexylamino)-1-propanesulfonic acid (CAPS) (w/v), 10% methanol (v/v) (pH 11). Proteins were visualized by staining with Coomassie brilliant blue R-250, and interesting bands were excised from the membrane for the analysis. Protein sequencing was performed in BioCentrum sp. z o.o. Service lab in Cracow, Poland. Amino acids abstracted sequentially from the N-terminus in the form of phenylthiohydantoin derivatives (PTH) were analyzed using the automatic sequencer Procise 491 (Applied Biosystems, Foster City, CA, USA) and following standard manufacturer’s protocols. Immunoblotting Proteins separated by SDS-PAGE were transferred onto polyvinylidene difluoride (PVDF) membrane (Immobilon P; Millipore). Following transfer, the membrane was blocked with 3% (w/v) low fat milk in TBS buffer for 1 h, and incubated 1 h with rabbit polyclonal antibodies against PssB cytoplasmic protein [39] or PssN outer membrane protein [40] diluted 1:20000 and 1:40000, respectively. The membrane was washed 3 times for 10 min with TBS, and incubated for 2 h with 1:30000 dilution of alkaline phosphate-conjugated goat anti-rabbit IgG (Sigma). The membrane was visualized with alkaline phosphatase substrates (nitro tetrazolium blue and 5-bromo-4-chloro-3-indolylphosphate, NBT/BCIP, Roche) in a color development buffer.