Family 2.A.18 - The Amino Acid/Auxin Permease Family
Family ID: 52623
The AAAP family includes over two dozen proteins from plants,
animals, yeast and fungi. Individual permeases of the AAAP family
transport auxin (indole-3-acetic acid), a single amino acid or
multiple amino acids. Some of these permeases exhibit very broad
specificities transporting all twenty amino acids naturally found
in proteins. There are 7 AAAP paralogues in Saccharomyces cerevisiae,
9 in Arabidopsis thaliana and 5 in Caenorhabditis elegans. These
proteins, all from eukaryotes, vary from 376 to 713 amino acyl
residues in length, but most are of 400-500 residues. Most of
the size variation occurs as a result of the presence of long
N-terminal hydrophilic extensions in some of the proteins. Some
of the yeast proteins are particularly long. Variation in the
loops and the C-termini also occurs. These proteins exhibit 11
putative transmembrane a-helical spanners. These proteins exhibit
limited sequence similarity with an amino acid permease (RocE)
of Bacillus subtilis (spP39137) which is a member of the large
APC family (TC #2.A.3). Thus, the AAAP family may be distantly
related to the APC family.
