Abstract
The pentatricopeptide repeat (PPR) is a degenerate 35-amino acid motif that is found in animal, fungi, and plants. A large gene family encoding PPR proteins particularly exists in plants, from a moss to flowering plants. PPR proteins have been shown to play important roles in the wide range of physiological and developmental functions. We previously reported that PPR531-11, one of the moss Physcomitrella patens PPR proteins, was involved in processing of clpP pre-mRNA in chloroplasts. In the present study, we have carried out RNA binding analysis of PPR531-11 using several clpP RNA fragments. The recombinant PPR531-11 expressed in Escherichia coli specifically bound to the upstream region from the cleavage site in the clpP and 5'-rps12 intergenic region. Taken together with the other biochemical data, we propose that the PPR531-11 is a sequence-specific RNA-binding protein and acts as a regulatory factor in plastid RNA processing of clpP pre-mRNA.
