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. The open reading frame (ORF) for this protein entirely encompasses the ORF for the 50S ribosomal protein L34 (rpmH). The two start codons are separated by four nucleotides. Belongs to the RnpA family.