BAP2, a gene encoding a permease for branched-chain amino acids in Saccharomyces cerevisiae

Biochim Biophys Acta. 1995 Nov 30;1269(3):275-80. doi: 10.1016/0167-4889(95)00138-8.


To select the gene coding for an isoleucine permease, an isoleucine dependent strain (ilv1 cha1) was transformed with a yeast genomic multicopy library, and colonies growing at a low isoleucine concentration were selected. Partial sequencing of the responsible plasmid insert revealed the presence of a previously sequenced 609 codon open reading frame of chromosome II with homology to known permeases. Deletion, extra dosage and C-terminal truncation of this gene were constructed in a strain lacking the general amino acid permease, and amino acid uptake was measured during growth in synthetic complete medium. The following observations prompted us to name the gene BAP2 (branched-chain amino acid permease). Deletion of BAP2 reduced uptake of leucine, isoleucine and valine by 25-50%, while the uptake of 8 other L-alpha-amino acids was unaltered or slightly increased. Introduction of BAP2 on a centromere-based vector, leading to a gene dosage of two or slightly more, caused a 50% increase in leucine uptake and a smaller increase for isoleucine and valine. However, when the 29 C-terminal codons of the plasmid-borne copy of BAP2 were substituted, the cells more than doubled the uptake of leucine, isoleucine and valine, while no or little increase in uptake was observed for the other 8 amino acids.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Amino Acid Transport Systems*
  • Amino Acids, Branched-Chain / metabolism*
  • Base Sequence
  • Biological Transport
  • Gene Deletion
  • Genes, Fungal*
  • Membrane Transport Proteins / genetics*
  • Membrane Transport Proteins / metabolism
  • Molecular Sequence Data
  • Promoter Regions, Genetic
  • Restriction Mapping
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins*
  • Sequence Alignment
  • Sequence Homology, Amino Acid


  • Amino Acid Transport Systems
  • Amino Acids, Branched-Chain
  • BAP2 protein, S cerevisiae
  • Membrane Transport Proteins
  • Saccharomyces cerevisiae Proteins