Part of an energy-coupled inorganic carbon pump. Probably involved in transport of dissolved inorganic carbon (DIC) with upstream gene dabB (Tcr_0853); has been suggested to be a proton-DIC symporter. Intracellular DIC accumulation is sensitive to CCCP (carbonyl cyanide-m-chlorophenylhydrazone) and DCCD (N,N-dicyclohexylcarbodiimide) and therefore likely driven by either proton potential, ATP, or both. Forms a complex with DabB. Induced by growth in low levels of dissolved inorganic carbon (DIC) (at protein level). Cells do not grow in low DIC levels, increased carboxysome content. Decreased ability to accumulate and fix DIC under DIC-limiting conditions. Belongs to the inorganic carbon transporter (TC 9.A.2) DabA family.