Involved in the D-alanylation of lipoteichoic acid (LTA). Could be responsible for the transfer of DltC-carried D-alanyl groups to cell membrane phosphatidylglycerol (PG), or alternatively of D-alanine residues from D-Ala-undecaprenol phosphate to the poly(glycerophosphate) chains of LTA. D-alanylation of LTA plays an important role in modulating the properties of the cell wall in Gram-positive bacteria, influencing the net charge of the cell wall. Cell wall biogenesis; lipoteichoic acid biosynthesis. Belongs to the DltD family.