Putative Amino Acid Permease

The putative amino acid permease (PAAP) family (TC# 2.A.120) is a member of the APC superfamily. The PAAP family consists of many proteins, all of a uniform topology with a 5 + 5 TMS repeat in a 2 + 3 + 2 + 3 arrangement. These proteins show similarity to members of the LIVCS family (TC# 2.A.26) in the APC Superfamily. As of August 2014, there has not been a single member that has been functionally characterized. However, a large majority of the genes encoding these transporters occur in operons or gene clusters encoding enzymes of amino acid metabolism. These include proteases, sporulation proteins, amino acid aminotransferases, amino acid and oxo acid oxidoreductases, and amino acid tRNA synthetases. A representative list of recognized members of the PAAP family is available in the Transporter Classification Database. As of early 2016, no crystal structural data are available for PAAP family members in RCSB.