Catalyzes the high-affinity uptake of extracellular proline. Important for the use of proline as a sole carbon and energy source or a sole nitrogen source. L-proline(in) + Na(+)(in) = L-proline(out) + Na(+)(out) The expression of the putBCP operon is induced in a PutR-dependent fashion by very low concentrations of L-proline in the growth medium. CodY represses the operon by displacing PutR from DNA. Deletion of the putBCP operon abolishes L-proline utilization. Belongs to the sodium:solute symporter (SSF) (TC 2.A.21) family. Truncated N-terminus.