6hd5
Cryo-EM structure of the ribosome-NatA complex
Structural highlights
Function[NAT1_YEAST] Non-catalytic component of the NatA N-terminal acetyltransferase, which catalyzes acetylation of proteins beginning with Met-Ser, Met-Gly and Met-Ala. N-acetylation plays a role in normal eukaryotic translation and processing, protect against proteolytic degradation and protein turnover. NAT1 anchors ARD1 and NAT5 to the ribosome and may present the N termini of nascent polypeptides for acetylation.[1] [2] [NAT5_YEAST] Non-essential component of the NatA N-terminal acetyltransferase, which catalyzes acetylation of proteins beginning with Met-Ser, Met-Gly and Met-Ala. N-acetylation plays a role in normal eukaryotic translation and processing, protect against proteolytic degradation and protein turnover. [ARD1_YEAST] Catalytic component of the NatA N-terminal acetyltransferase, which catalyzes acetylation of proteins beginning with Met-Ser, Met-Gly and Met-Ala. N-acetylation plays a role in normal eukaryotic translation and processing, protect against proteolytic degradation and protein turnover.[3] Publication Abstract from PubMedThe majority of eukaryotic proteins are N-terminally alpha-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. Ribosome-NatA architecture reveals that rRNA expansion segments coordinate N-terminal acetylation.,Knorr AG, Schmidt C, Tesina P, Berninghausen O, Becker T, Beatrix B, Beckmann R Nat Struct Mol Biol. 2018 Dec 17. pii: 10.1038/s41594-018-0165-y. doi:, 10.1038/s41594-018-0165-y. PMID:30559462[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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