RNaseP catalyzes the removal of the 5'-leader sequence from pre-tRNA to produce the mature 5'-terminus. It can also cleave other RNA substrates such as 4.5S RNA. The protein component plays an auxiliary but essential role in vivo by binding to the 5'-leader sequence and broadening the substrate specificity of the ribozyme. Endonucleolytic cleavage of RNA, removing 5'-extranucleotides from tRNA precursor. Consists of a catalytic RNA component (M1 or rnpB) and a protein subunit (By similarity). Homodimer (Probable). Component of a possible RNA degradosome complex composed of cshA, eno, pfkA, pnp, rnjA, rnjB, rnpA and rny. Interacts specifically with RNA helicase CshA. Belongs to the RnpA family.