Plays a major role in single RNA editing events in chloroplasts. Acts as a site-recognition transacting factor involved in the edition of the unique site (corresponding to cytidine-488) of rpoC1, which is a plastid-encoded subunit of the chloroplast DNA-directed RNA polymerase. May provide the catalytic activity for editing site conversion (PubMed:24194514). Involved in leaf vasculature patterning (PubMed:18643975). Binds 2 zinc ions per subunit. Weakly expressed in leaves. Defects in venation pattern in leaves and cotyledons. Belongs to the PPR family. PCMP-H subfamily.