Binds specific group II introns in chloroplasts and facilitates their splicing. Acts on both subgroup IIA and subgroup IIB introns. The substrates of the subgroup IIB also require the CRM domain proteins CAF1 or CAF2, with a simultaneous binding of CFM2 and CAF1 or CAF2. Can bind to and promote the splicing of the single group I intron in chloroplast tRNA transcript of trnL-UAA gene. Interacts with RNA. Part of large ribonucleo-protein particles that contain CAF1 and/or CAF2. Albino seeds that germinate poorly and die soon after germination.