Summary information and primary citation
- PDB-id
-
3iy8;
DSSR-derived features in text and
JSON formats
- Class
- ribosome
- Method
- cryo-EM (14.1 Å)
- Summary
- Leishmania tarentolae mitonchondrial ribosome small
subunit
- Reference
-
Sharma MR, Booth TM, Simpson L, Maslov DA, Agrawal RK
(2009): "Structure
of a mitochondrial ribosome with minimal RNA."
Proc.Natl.Acad.Sci.USA, 106,
9637-9642. doi: 10.1073/pnas.0901631106.
- 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).
