Solution structure of an archaeal RNase P binary protein complex: formation of the 30-kDa complex between Pyrococcus furiosus RPP21 and RPP29 is accompanied by coupled protein folding and highlights critical features for protein-protein and protein-RNA interactions.
Ribonuclease P (RNase P) is a ribonucleoprotein (RNP) enzyme that catalyzes the Mg(2+)-dependent 5' maturation of precursor tRNAs. In all domains of life, it is a ribozyme: the RNase P RNA (RPR) component has been demonstrated to be responsible for catalysis. However, the number of RNase P protein subunits (RPPs) varies from 1 in bacteria to 9 or 10 in eukarya. The archaeal RPR is associated with at least 4 RPPs, which function in pairs (RPP21-RPP29 and RPP30-POP5). We used solution NMR spectroscopy to determine the three-dimensional structure of the protein-protein complex comprising Pyrococcus furiosus RPP21 and RPP29. We found that the protein-protein interaction is characterized by coupled folding of secondary structural elements that participate in interface formation. In addition to detailing the intermolecular contacts that stabilize this 30-kDa binary complex, the structure identifies surfaces rich in conserved basic residues likely vital for recognition of the RPR and/or precursor tRNA. Furthermore, enzymatic footprinting experiments allowed us to localize the RPP21-RPP29 complex to the specificity domain of the RPR. These findings provide valuable new insights into mechanisms of RNP assembly and serve as important steps towards a three-dimensional model of this ancient RNP enzyme.
Xu
Yiren
Y
Ohio State Biochemistry Program, Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA.
Amero
Carlos D
CD
Pulukkunat
Dileep K
DK
Gopalan
Venkat
V
Foster
Mark P
MP
D019843:Archaeal Proteins / Q000737:chemistry* / Q000378:metabolism*; D001665:Binding Sites; D018983:DNA Footprinting; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D011485:Protein Binding; D017510:Protein Folding; D017433:Protein Structure, Secondary; D020027:Pyrococcus furiosus / Q000737:chemistry*; D019642:RNA, Archaeal / Q000378:metabolism*; D043262:Ribonuclease P / Q000737:chemistry*; D012996:Solutions; D055672:Static Electricity
D019843:Archaeal Proteins; D019642:RNA, Archaeal; D012996:Solutions; D043262:Ribonuclease P