4X4U

Crystal structure of the A.fulgidus CCA-adding enzyme in complex with a human MenBeta minihelix ending in CCACC

Summary for 4X4U

• Entry DOI: 10.2210/pdb4x4u/pdb
• Related: 4X4N 4X4O 4X4P 4X4Q 4X4R 4X4S 4X4T 4X4V 4X4W 4X4X
• Descriptor: CCA-adding enzyme, human MenBeta minihelix, RNA (5'-D(*GP*G)-3'), ... (7 entities in total)
• Functional Keywords: protein-rna complex, trna, non-coding rna, cca-adding enzyme, nucleotidyltransferase, ncrna, rna binding protein
• Biological source: Archaeoglobus fulgidus; More
• Total number of polymer chains: 8
• Total formula weight: 252676.71

Authors

Kuhn, C.-D.,Joshua-Tor, L. (deposition date: 2014-12-03, release date: 2015-02-11, Last modification date: 2023-12-27)

Primary citation

Kuhn, C.D.,Wilusz, J.E.,Zheng, Y.,Beal, P.A.,Joshua-Tor, L.
On-Enzyme Refolding Permits Small RNA and tRNA Surveillance by the CCA-Adding Enzyme.
Cell, 160:644-658, 2015

PubMed Abstract: Transcription in eukaryotes produces a number of long noncoding RNAs (lncRNAs). Two of these, MALAT1 and Menβ, generate a tRNA-like small RNA in addition to the mature lncRNA. The stability of these tRNA-like small RNAs and bona fide tRNAs is monitored by the CCA-adding enzyme. Whereas CCA is added to stable tRNAs and tRNA-like transcripts, a second CCA repeat is added to certain unstable transcripts to initiate their degradation. Here, we characterize how these two scenarios are distinguished. Following the first CCA addition cycle, nucleotide binding to the active site triggers a clockwise screw motion, producing torque on the RNA. This ejects stable RNAs, whereas unstable RNAs are refolded while bound to the enzyme and subjected to a second CCA catalytic cycle. Intriguingly, with the CCA-adding enzyme acting as a molecular vise, the RNAs proofread themselves through differential responses to its interrogation between stable and unstable substrates.

PubMed: 25640237
DOI: 10.1016/j.cell.2015.01.005

Experimental method

X-RAY DIFFRACTION (2.7 Å)