Different cleavage sites are aligned differently in the active site of M1 RNA, the catalytic subunit of Escherichia coli RNase P

作者：Kufel J; Kirsebom LA

来源：Proceedings of the National Academy of Sciences of the United States of America, 1996, 93(12): 6085-6090.

DOI：10.1073/pnas.93.12.6085

• ribozyme
• tRNA precursors
• tRNA processing

We have studied RNase P RNA (M1 RNA) cleavage of model tRNA precursors that are cleaved at two independent positions. Here we present data demonstrating that cleavage at both sites depends on the 2'-OH immediately 5' of the respective cleavage site. However, we show that the 2-amino group of a guanosine at the cleavage site plays a significant role in cleavage at one of these sites but not at the other, These data suggest that these two cleavage sites are handled differently by the ribozyme. This theory is supported by our finding that the cross-linking pattern between M1 RNA and tRNA precursors carrying 4-thio U showed distinct differences, depending on the location of the 4-thio U relative to the respective cleavage site. These findings lead us to suggest that different cleavage sites are aligned differently in the active site, possibly as a result of different binding modes of a substrate to M1 ENA. We discuss a model in which the interaction between the 3'-terminal ''RCCA'' motif (interacting residues are underlined) of a tRNA precursor and M1 RNA plays a significant role in this process.

• 出版日期1996-6-11