The bacterial PIcR helix-turn-helix transcription factor includes five TPR units of different lengths [1]. This entry represents the TPR containing domain as a whole. This family is called RNPP after (Rapm NprR, PrgX, and PlcR).

1: Structural basis for the activation mechanism of the PlcR virulence regulator by the quorum-sensing signal peptide PapR. Grenha R, Slamti L, Nicaise M, Refes Y, Lereclus D, Nessler S; Proc Natl Acad Sci U S A. 2013;110:1047-1052. PMID:23277548