Precursor tRNA Processing by Protein Only RNase Ps and its Connection to Mitochondrial Diseases
Abstract
A plethora of human diseases are linked to mutations in human mitochondrial transfer RNAs (tRNA). In most cases, it is unknown how these mutations contribute to disease. tRNAs are matured by several enzymes acting in a sequential manner. Mutations in tRNAs could impair interactions with these enzymes causing precursor RNA accumulation leading to mitochondrial dysfunction. RNase P is one of the first tRNA maturation enzymes catalyzing the removal of the 5 extraneous end of precursor tRNAs. Protein Only RNase Ps (PRORPs) are foundin eukaryotes and divided into two major classes. In most unicellular eukaryotes and plants, PRORPs are stand-alone enzymes that localize in the nucleus and organelles, while metazoan PRORPs, also known as MRPP3s (Mitochondrial RNase P Protein), are found only in mitochondria and form the mitochondrial RNase P complex with accessory partners MRPP1 and 2. mtRNase P is proposed to play a central role in human health and disease. Despite the importance of PRORPs, knowledge of their structure and function and their relations to human diseases is still very limited. Hence, I have investigated the following overall questions: (1) How do PRORPs recognize and cleave their substrates? (2) Are PRORPs structurally conserved? (3) Is there any link between PRORPs and mitochondrial diseases? In order to answer these questions I studied a stand-alone PRORP (PRORP2 from A.thaliana) and human MRPP3 using X-ray crystallography and biochemical assays. I found that the biochemical and structural properties of PRORP2 are highly conserved with minor differences compared to other A.thaliana paralogs. Furthermore, my work resulted in a detailed model of PRORP-substrate interactions. Later, I demonstrated that single unit and multi-subunit PRORPs employ different substrate recognition mechanisms. In addition, I observed that there is a complex interplay between components of mtRNase P that can drive substrate recognition.
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 14, 2018
- Accession Number
- AD1128429
Entities
People
- Agnes Karasik
Organizations
- Uniformed Services University of the Health Sciences