CRR21 (CHLORORESPIRATORY REDUCTION 21). similar to pentatricopeptide (PPR) repeat-containing protein [Arabidopsis thaliana] (TAIR:AT4G21300.1); similar to unnamed protein product [Vitis vinifera] (GB:CAO65596.1); contains InterPro domain Pentatricopeptide repeat (InterPro:IPR002885)