L-aspartate transport in the photosynthetic bacterium Chromatium vinosum.

The photosynthetic purple sulfur bacterium Chromatium vinosum appears to contain two active transport systems for L-aspartate. The higher affinity system (S0.5 = 60 microM) appears to be an electrogenic aspartate/H+ symport and the lower affinity system (S0.5 = 220 microM) appears to involve an aspartate/Na+ symport. In addition to a possible role in providing the driving force for aspartate uptake, transmembrane Na+ gradients may also have allosteric effects on aspartate transport in C. vinosum.