3IY9

Leishmania Tarentolae Mitochondrial Large Ribosomal Subunit Model

Summary for 3IY9

• Entry DOI: 10.2210/pdb3iy9/pdb
• Related: 3IY8
• EMDB information: 5113
• Descriptor: Leishmania Tarentolae Mitochondrial Large Ribosomal Subunit, 39S ribosomal protein L16, mitochondrial, 39S ribosomal protein L17, mitochondrial, ... (20 entities in total)
• Functional Keywords: leishmania tarentolae, mitochondrial ribosome, cryoem, minimal rna., mitochondrion, ribonucleoprotein, ribosomal protein, transit peptide, methylation, rna-binding, rrna-binding, ribosome
• Biological source: Leishmania Tarentolae; More
• Total number of polymer chains: 20
• Total formula weight: 564864.71

Authors

Sharma, M.R.,Booth, T.M.,Simpson, L.,Maslov, D.A.,Agrawal, R.K. (deposition date: 2009-04-20, release date: 2009-07-07, Last modification date: 2024-02-21)

Primary citation

Sharma, M.R.,Booth, T.M.,Simpson, L.,Maslov, D.A.,Agrawal, R.K.
Structure of a mitochondrial ribosome with minimal RNA
Proc.Natl.Acad.Sci.USA, 106:9637-9642, 2009

PubMed Abstract: The Leishmania tarentolae mitochondrial ribosome (Lmr) is a minimal ribosomal RNA (rRNA)-containing ribosome. We have obtained a cryo-EM map of the Lmr. The map reveals several features that have not been seen in previously-determined structures of eubacterial or eukaryotic (cytoplasmic or organellar) ribosomes to our knowledge. Comparisons of the Lmr map with X-ray crystallographic and cryo-EM maps of the eubacterial ribosomes and a cryo-EM map of the mammalian mitochondrial ribosome show that (i) the overall structure of the Lmr is considerably more porous, (ii) the topology of the intersubunit space is significantly different, with fewer intersubunit bridges, but more tunnels, and (iii) several of the functionally-important rRNA regions, including the alpha-sarcin-ricin loop, have different relative positions within the structure. Furthermore, the major portions of the mRNA channel, the tRNA passage, and the nascent polypeptide exit tunnel contain Lmr-specific proteins, suggesting that the mechanisms for mRNA recruitment, tRNA interaction, and exiting of the nascent polypeptide in Lmr must differ markedly from the mechanisms deduced for ribosomes in other organisms. Our study identifies certain structural features that are characteristic solely of mitochondrial ribosomes and other features that are characteristic of both mitochondrial and chloroplast ribosomes (i.e., organellar ribosomes).

PubMed: 19497863
DOI: 10.1073/pnas.0901631106

Experimental method

ELECTRON MICROSCOPY (14.1 Å)