Expansion of the APC superfamily of secondary carriers.

摘要: The amino acid-polyamine-organoCation (APC) superfamily is the second largest of secondary carriers currently known. In this study, we establish homology between previously recognized APC members and proteins seven new families. These families include PAAP (Putative Amino Acid Permease), LIVCS (Branched Chain Acid:Cation Symporter), NRAMP (Natural Resistance-Associated Macrophage Protein), CstA (Carbon starvation A protein), KUP (K⁺ Uptake BenE (Benzoate:H⁺ Virginia AE (Anion Exchanger). topology well-characterized human Anion Exchanger 1 (AE1) conforms to a UraA-like 14 TMSs (12 α-helical 2 mixed coil/helical TMSs). All functionally characterized use cation symport for substrate accumulation except some family which frequently anion:anion exchange. We show how different topologies fit into framework common LeuT-like fold, defined earlier (Proteins. 2014 Feb;82(2):336-46), determine that contain undocumented topological variations. entries two 5 or 7 TMS repeat units, sometimes with extra at ends, variations being greatest within family. New, transport acids, peptides, inorganic anions cations. Except anions, these are typical substrates established members. Active site rich in glycyl residues variable but conserved constellations. This work expands our understanding its