Involved in the biogenesis of the plastid translation machinery by promoting the splicing of group II introns in chloroplasts. Stabilizes the chloroplast trnG pre-RNA by directly binding to a group II intron, where it protects an endonuclease-sensitive site and stimulates splicing (PubMed:18591259). Binds specific sites within group II intron trnG pre-RNA. Binds with high affinity to the 5'-UTR of the chloroplastic petA mRNA (PubMed:18669444). Albino or pale green seedlings. Seedling lethality. Belongs to the PPR family. P subfamily.