Journal article

Isolation and characterization of two ammonium permease genes, meaA and mepA, from Aspergillus nidulans

BJ Monahan, JA Fraser, MJ Hynes, MA Davis

EUKARYOTIC CELL | AMER SOC MICROBIOLOGY | Published : 2002

Abstract

Ammonium and the analogue methylammonium are taken into the cell by active transport systems which constitute a family of transmembrane proteins that have been identified in fungi, bacteria, plants, and animals. Two genes from Aspergillus nidulans, mepA and meaA, which encode ammonium transporters with different affinities have been characterized. The MepA transporter exhibits the highest affinity for methylammonium (Km, 44.3 microM); in comparison, the Km for MeaA is 3.04 mM. By use of targeted gene replacement strategies, meaA and mepA deletion mutants were created. Deletion of both meaA and mepA resulted in the inability of the strain to grow on ammonium concentrations of less than 10 mM...

View full abstract