RNA-binding protein involved in group II intron splicing. Binds specific group II introns and promotes their splicing (e.g. rpl2 and ccmFC). Severely stunted shoots and roots, small flowers with very small anthers and little pollen, and very small siliques containing only a few aborted seeds. Impaired splicing of rpl2 and ccmFC mRNAs. Absence of c-type cytochromes, complex III and cytochrome oxidase.