With no explanation, label text_A→text_B with either "not_related" or "related".
text_A: How I Met Your Mother had 208 episodes.
text_B: The pentatricopeptide repeat -LRB- PPR -RRB- is a 35-amino acid sequence motif .. amino acid. amino acid. sequence motif. sequence motif. Pentatricopeptide-repeat-containing proteins are a family of proteins commonly found in the plant kingdom .. proteins. proteins. plant. plant. They are distinguished by the presence of tandem degenerate PPR motifs and by the relative lack of introns in the genes coding for them .. introns. introns. Approximately 450 such proteins have been identified in the Arabidopsis genome , and another 477 in the rice genome .. proteins. proteins. Arabidopsis. Arabidopsis thaliana. rice. rice. Despite the large size of the protein family , genetic data suggest that there is little or no redundancy of function between the PPR proteins in Arabidopsis .. proteins. proteins. Arabidopsis. Arabidopsis thaliana. The purpose of PPR proteins is currently under dispute .. proteins. proteins. It has been shown that a good deal of those in Arabidopsis interact -LRB- often essentially -RRB- with mitochondria and other organelles and that they are possibly involved in RNA editing .. Arabidopsis. Arabidopsis thaliana. mitochondria. mitochondria. organelles. organelles. RNA editing. RNA editing. However many trans proteins are required for this editing to occur and research continues to look at which proteins are needed .. proteins. proteins. The structure of the PPR has not yet been determined , the motif is predicted to fold into a helix-turn-helix structure similar to those found in the tetratricopeptide repeat .. helix-turn-helix. helix-turn-helix. tetratricopeptide. tetratricopeptide
not_related.