Amino acid transport by membrane vesicles of an obligate anaerobic bacterium, Clostridium acetobutylicum

Abstract

Membrane vesicles were isolated from the obligate anaerobic bacterium Clostridium acetobutylicum. Beef heart mitochondrial cytochrome c oxidase was inserted in these membrane vesicles by membrane fusion by using the freeze-thaw sonication technique (A. J. M. Driessen, W. de Vrij, and W. N. Konings, Proc. Natl. Acad. Sci. USA 82:7555-7559, 1985) to accommodate them with a functional proton motive force-generating system. With ascorbate-N,N,N',N'-tetramethyl-p-phenylenediamine-cytochrome c as the electron donor, a proton motive force (delta p) of -80 to -120 mV was generated in these fused membranes. This delta p drove the accumulation of leucine and lysine up to 40- and 100-fold, respectively. High transport activities were observed in fused membranes containing Escherichia coli lipids, whereas the transport activities in fused membranes containing mainly soybean lipids or phosphatidylcholine were low. It is suggested that branched-chain amino acids and lysine were taken up by separate systems. The effects of the ionophores nigericin and valinomycin indicated that lysine and leucine were translocated in symport with a proton.

Secondary solute transport in bacteria

“…Electrogenic uptake of neutral solutes in bacteria has been shown for sugars and amino acids [11,16,[36][37][38][39]. Electrogenic cationic solute-proton (or sodium ion) symport has been observed for the uptake of arginine and lysine in a number of bacteria [11,[40][41][42]. For electrogenie anionproton (or sodium ion) symport two extremes exist, i.e., the ziqt may oppose or contribute to the driving force ( Fig.…”

The bacteriocin lactococcin A specifically increases permeability of lactococcal cytoplasmic membranes in a voltage-independent, protein-mediated manner

“…E. coli ML308-225 and B. subtilis W23 were grown as described by Kaback (12) and de Vrij et al (3), respectively. Clostridium acetobutylicum NCIB 8025 was grown as described by Driessen et al (5). Lactococcin A was purified as described previously (10) and stored at a concentration of 0.2 mg/ml in 60% ethanol-2.5 mM sodium phosphate (pH 7.3) at -20°C.…”

Electrotransformation of Clostridium acetobutylicum ATCC 824 using high-voltage radio frequency modulated square pulses

“…There are reports that members of Clostridium genus can form closed membrane structures under conditions facilitating osmotic lysis (Driessen et al 1988), or demonstrate fragmentation of the peripheral parts of the cytoplasm by membrane components in mechanically disrupted cells (Vysotskii and Gorshkova 1978). This information led us to investigate a possible correlation of pulse current generated during membrane disruption with increased efficiency of ET of Cl.…”