5H1S

Structure of the large subunit of the chloro-ribosome

Summary for 5H1S

• Entry DOI: 10.2210/pdb5h1s/pdb
• EMDB information: 9572
• Descriptor: 23S rRNA, 50S ribosomal protein L19, chloroplastic, 50S ribosomal protein L20, chloroplastic, ... (32 entities in total)
• Functional Keywords: cryo-em, ribosome, chloro-ribosome
• Biological source: Spinacia oleracea (Spinach); More
• Total number of polymer chains: 32
• Total formula weight: 1445311.21

Authors

Ahmed, T.,Yin, Z.,Bhushan, S. (deposition date: 2016-10-11, release date: 2017-02-01, Last modification date: 2025-09-17)

Primary citation

Ahmed, T.,Yin, Z.,Bhushan, S.
Cryo-EM structure of the large subunit of the spinach chloroplast ribosome.
Sci Rep, 6:35793-35793, 2016

PubMed Abstract: Protein synthesis in the chloroplast is mediated by the chloroplast ribosome (chloro-ribosome). Overall architecture of the chloro-ribosome is considerably similar to the Escherichia coli (E. coli) ribosome but certain differences are evident. The chloro-ribosome proteins are generally larger because of the presence of chloroplast-specific extensions in their N- and C-termini. The chloro-ribosome harbours six plastid-specific ribosomal proteins (PSRPs); four in the small subunit and two in the large subunit. Deletions and insertions occur throughout the rRNA sequence of the chloro-ribosome (except for the conserved peptidyl transferase center region) but the overall length of the rRNAs do not change significantly, compared to the E. coli. Although, recent advancements in cryo-electron microscopy (cryo-EM) have provided detailed high-resolution structures of ribosomes from many different sources, a high-resolution structure of the chloro-ribosome is still lacking. Here, we present a cryo-EM structure of the large subunit of the chloro-ribosome from spinach (Spinacia oleracea) at an average resolution of 3.5 Å. High-resolution map enabled us to localize and model chloro-ribosome proteins, chloroplast-specific protein extensions, two PSRPs (PSRP5 and 6) and three rRNA molecules present in the chloro-ribosome. Although comparable to E. coli, the polypeptide tunnel and the tunnel exit site show chloroplast-specific features.

PubMed: 27762343
DOI: 10.1038/srep35793

Experimental method

ELECTRON MICROSCOPY (3.5 Å)