A D-serine-specific transporter, may function as a H(+) symporter. By growth in D-serine, controlled by DsdC. Belongs to the GntP permease family. An ORF called dsdC was originally (PubMed:3275618) assigned to the wrong DNA strand and thought to be a D-serine deaminase activator, it was then resequenced by Ref.2 and still thought to be 'dsdC', but this time to function as a D-serine permease. It is PubMed:7592420 that showed that dsdC is another gene and that this sequence should be called dsdX. It should also be noted that the C-terminal part of dsdX (from 338 onward) was also sequenced (PubMed:3029015 and PubMed:1659648) and was thought to be a separate ORF (don't worry, we also had difficulties understanding what happened!).