Fully-grown cultures were opened under anaerobic conditions (97:3 N2:H2) and moved into centrifugation beakers. Cells were harvested at 4500 x g 4 °C for 45 min. The cell pellet was resuspended in a 1:1 ratio with 20 mM TEA/HCl buffer pH 7.8 and homogenized with ultrasonication (20 mHz, 20% amplitude, 3 s pulse with 9 s pause for 20 min; Sonifier 250, Branson) while cooled with solid ice packs to prevent denaturation. Permeabilized cells were ultra-centrifuged at 100 000 x g, 4 °C for 1 hour. The supernatant was collected and the obtained cell-free extract was stored at -80 ⁰C until use under the blanketing atmosphere of N2/H2. The protein concentration of the cell extract was determined in a 2 L spectroscopic method (280 and 260 nm, BioTek with Take3 plate) yielding 39 ± 0.9 mg/ml.