After incubation, cells were collected by centrifugation (4500 × g, 5 min, RT) and washed twice with PBS, pH 7.4 (8.0 g NaCl, 0.2 g KCl, 1.44 g Na2HPO4, 0.24 g KH2PO4). The see more supernatant was removed and the pelleted cells were washed with 1 ml PBS and subjected to a further short centrifugation step (4500 × g, 1 min, RT). The supernatant was removed and 30 – 100 μl PBS were added to the wet cell pellet. Proteins from resuspended cells were extracted

by boiling at 90°C for 10 min. The suspension was centrifuged at 10000 × g and 4°C for 10 min and the supernatant was transferred to a new 1.5 ml Eppendorf tube. This centrifugation step was repeated once to remove residual cells. The protein extract (supernatant) was subjected to protein determination using bicinchoninic

acid [60]. Equal protein concentrations in all samples were obtained GSK2879552 mw by diluting the samples with PBS according to the concentration of the least concentrated sample. All protein samples were mixed with 5x protein sample buffer (1.5 g sodium dodecyl sulphate (SDS), 1.116 g dithiothreitol, Small Molecule Compound Library 0.015 g bromphenol blue, 7.5 ml 0.5 M Tris HCl pH 6.8, 7.5 ml glycerol) in a ratio of 4:1, boiled at 95°C for 10 min and stored at −20°C until use. Proteins (60 – 70 μg) were separated on freshly prepared 1 D SDS-gels containing 12.5% running gel and 4% stacking gel (Rotiphorese® Gel 30 (37.5:1), Roth, Karlsruhe, Germany). Gels were run at 120 V for up to 3 h (unless otherwise mentioned), before staining with coomassie staining solution (0.25% Coomassie-G25, 50% H2O, 42% Ethanol, 8% acetic acid) at RT for 30 Quinapyramine min followed by

destaining with distilled water (dH2O) overnight with an occasional interval in destaining solution (50% H2O, 42% Ethanol, 8% acetic acid) for no longer than 15 minutes. Gel documentation was performed with the GS-800 gel scanner (Bio-Rad, München, Germany). In the figures only those parts of the gels are shown, which contain the bands, which are relevant for the results described here. Occasionally, after documentation distorted bands were bent to obtain almost straight bands. For MALDI-TOF peptide mass fingerprinting protein bands were cut out from 1D SDS-gels, reduced and carboxamidomethylated, and then subjected to in-gel tryptic digestion. The resulting peptides were extracted, desalted using ZipTip devices (Millipore, Bedford, USA) and analyzed by MALDI-TOF-MS using a Bruker Ultraflex time-of-flight mass spectrometer (Bruker Daltonics, Bremen, Germany). Laser induced dissociation of selected peptides for sequence confirmation was performed on the same instrument. Identification of proteins was performed with the mascot search engine at http://​www.​matrixscience.​com/​. For N-terminal sequencing, proteins were blotted on polyvinylidene fluoride (PVDF) membranes and stained with Coomassie G-25 at room temperature for 5 min. Background color was removed by incubation in destaining solution for 30 min.