4XGM: Structure Of The Nuclease Subunit Of Human Mitochondrial Rnase P (mrpp3) At 1.98a

Mitochondrial RNA polymerase produces long polycistronic precursors that contain the mRNAs, rRNAs and tRNAs needed for mitochondrial translation. Mitochondrial RNase P (mt-RNase P) initiates the maturation of the precursors by cleaving at the 5' ends of the tRNAs. Human mt-RNase P is only active as a tripartite complex (mitochondrial RNase P proteins 1-3; MRPP1-3), whereas plant and trypanosomal RNase Ps (PRORPs)-albeit homologous to MRPP3-are active as single proteins. The reason for this discrepancy has so far remained obscure. Here, we present the crystal structure of human MRPP3, which features a remarkably distorted and hence non-productive active site that we propose will switch to a fully productive state only upon association with MRPP1, MRPP2 and pre-tRNA substrate. We suggest a mechanism in which MRPP1 and MRPP2 both deliver the pre-tRNA substrate and activate MRPP3 through an induced-fit process.
PDB ID: 4XGMDownload
MMDB ID: 129266
PDB Deposition Date: 2014/12/31
Updated in MMDB: 2015/07
Experimental Method:
x-ray diffraction
Resolution: 1.98  Å
Source Organism:
Similar Structures:
Biological Unit for 4XGM: monomeric; determined by author and by software (PISA)
Molecular Components in 4XGM
Label Count Molecule
Protein (1 molecule)
Mitochondrial Ribonuclease P Protein 3(Gene symbol: KIAA0391)
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB