Cell-Free and Yeast-Based Production of the Malarial Lactate Transporter, PfFNT, Delivers Comparable Yield and Protein Quality.

Cell-free protein production is an attractive alternative to cell-based expression. Rapid results, small-volume reactions, irrelevance of protein toxicity, flexibility, and openness of the system are strong points in favor of the cell-free system. However, the situation lacks the cellular quality control machinery comprising e.

Formate-nitrite transporters carrying nonprotonatable amide amino acids instead of a central histidine maintain pH-dependent transport.

Microbial formate-nitrite transporter-type proteins (FNT) exhibit dual transport functionality. At neutral pH, electrogenic anion currents are detectable, whereas upon acidification transport of the neutral, protonated monoacid predominates. Physiologically, FNT-mediated proton co-transport is vital when monocarboxylic acid products of the energy metabolism, such as l-lactate, are released from the cell.

High-level cell-free production of the malarial lactate transporter PfFNT as a basis for crystallization trials and directional transport studies.

The malaria parasite Plasmodium falciparum relies on the function of channel and transport proteins for the uptake of nutrients and the release of metabolic waste products. Inhibition of vital transport processes is an unexploited means for developing novel antimalarial drugs. The recently discovered plasmodial lactate transporter, PfFNT, represents a promising new drug target since the parasite's energy generation by anaerobic glycolysis depends on the rapid secretion of lactate.