9T3L

Crystal structure of the Acl1 ankyrin repeat domain in complex with the second Rpl1 domain

Summary for 9T3L

• Entry DOI: 10.2210/pdb9t3l/pdb
• Descriptor: Large ribosomal subunit protein uL1A, Ankyrin repeat-containing protein YCR051W (3 entities in total)
• Functional Keywords: ribosome assembly, chaperone complex, ankyrin repeat domain, protein-protein interaction, ribosomal protein
• Biological source: Saccharomyces cerevisiae (brewer's yeast); More
• Total number of polymer chains: 2
• Total formula weight: 25803.17

Authors

Burchert, F.,Kiontke, S.,Bange, G. (deposition date: 2025-10-28, release date: 2026-04-08)

Primary citation

Favre, S.,Pillet, B.,Burchert, F.,Siva Sankar, D.,Mendez-Godoy, A.,Kiontke, S.,Dengjel, J.,Bange, G.,Kressler, D.
Exploration of the proxiOME of large subunit ribosomal proteins reveals Acl1 and Bcl1 as cooperating dedicated chaperones of Rpl1.
Nucleic Acids Res., 54:-, 2026

PubMed Abstract: In eukaryotes, most newly synthesized ribosomal proteins (r-proteins) need to rapidly and safely get into the nucleus to reach their assembly site on pre-ribosomal particles. However, only for few r-proteins tailored support mechanisms involving so-called dedicated chaperones (DCs) could so far be revealed. Here, with the primary aim of identifying novel DCs, we performed TurboID-based proximity labelling with all 46 large subunit r-proteins of Saccharomyces cerevisiae, which unveiled the fungi-specific Acl1 and the conserved Bcl1 as candidate DCs of Rpl1. We show that the functionally cooperating Acl1 and Bcl1 both directly interact with Rpl1, form a trimeric Acl1-Rpl1-Bcl1 complex, and enable the nuclear import of Rpl1. Moreover, our crystal structure of the minimal Acl1-Rpl1 complex reveals how Acl1's ankyrin repeat domain shields a positively charged ribosomal RNA-binding surface of Rpl1. Our proximity labelling approach also permitted to establish novel interactions between four r-proteins and distinct importins and to illuminate r-protein neighbourhoods on successive pre-60S particles. Additionally, reciprocal proximity labelling with the known DCs indicates that almost all appear to be transiently associated with pre-ribosomal particles. Our study provides for the first time comprehensive insight into the physical proximities of large subunit r-proteins along their entire life cycle.

PubMed: 41909949
DOI: 10.1093/nar/gkag264

Experimental method

X-RAY DIFFRACTION (2.55 Å)