6HD5

Cryo-EM structure of the ribosome-NatA complex

Summary for 6HD5

• Entry DOI: 10.2210/pdb6hd5/pdb
• Related: 4kvm 4xnh
• EMDB information: 0201
• Descriptor: N-terminal acetyltransferase A complex subunit NAT1, N-terminal acetyltransferase A complex catalytic subunit ARD1, N-alpha-acetyltransferase NAT5 (3 entities in total)
• Functional Keywords: n-terminal acetylation, protein modification, ribosome, expansion segments, translation
• Biological source: Saccharomyces cerevisiae (strain ATCC 204508 / S288c); More
• Total number of polymer chains: 3
• Total formula weight: 146439.03

Authors

Knorr, A.G.,Becker, T.,Beckmann, R. (deposition date: 2018-08-17, release date: 2018-12-19, Last modification date: 2024-05-15)

Primary citation

Knorr, A.G.,Schmidt, C.,Tesina, P.,Berninghausen, O.,Becker, T.,Beatrix, B.,Beckmann, R.
Ribosome-NatA architecture reveals that rRNA expansion segments coordinate N-terminal acetylation.
Nat. Struct. Mol. Biol., 26:35-39, 2019

PubMed Abstract: The majority of eukaryotic proteins are N-terminally α-acetylated by N-terminal acetyltransferases (NATs). Acetylation usually occurs co-translationally and defects have severe consequences. Nevertheless, it is unclear how these enzymes act in concert with the translating ribosome. Here, we report the structure of a native ribosome-NatA complex from Saccharomyces cerevisiae. NatA (comprising Naa10, Naa15 and Naa50) displays a unique mode of ribosome interaction by contacting eukaryotic-specific ribosomal RNA expansion segments in three out of four binding patches. Thereby, NatA is dynamically positioned directly underneath the ribosomal exit tunnel to facilitate modification of the emerging nascent peptide chain. Methionine amino peptidases, but not chaperones or signal recognition particle, would be able to bind concomitantly. This work assigns a function to the hitherto enigmatic ribosomal RNA expansion segments and provides mechanistic insights into co-translational protein maturation by N-terminal acetylation.

PubMed: 30559462
DOI: 10.1038/s41594-018-0165-y

Experimental method

ELECTRON MICROSCOPY (4.8 Å)