Ribonucleoprotein Ribonucleases P and MRP

Abstract

Ribonucleoprotein Ribonuclease (RNase) P and RNase MRP consist of a large RNA component and an essential protein part. RNases P/MRP differ from all other known ribonucleases in that it is their RNA component, not protein that is responsible for the endonucleolytic cleavage of substrates. RNase P is universally essential in all three domains of life; the closely related RNase MRP is a ubiquitous eukaryotic enzyme. RNase P is primarily responsible for the maturation of the 5′-ends of tRNA, whereas RNase MRP is known to be involved in the maturation of eukaryotic rRNA and the degradation of specific mRNAs. Here we discuss available information on functions, structural organization, and mechanisms of substrate recognition and catalysis of RNases P/MRP.