The structure of Rpf2–Rrs1 explains its role in ribosome biogenesis

Abstract

The assembly of eukaryotic ribosomes is a hierarchical process involving about 200 biogenesis factors and a series of remodeling steps. The 5S RNP consisting of the 5S rRNA, RpL5 and RpL11 is recruited at an early stage, but has to rearrange during maturation of the pre-60S ribosomal subunit. Rpf2 and Rrs1 have been implicated in 5S RNP biogenesis, but their precise role was unclear. Here, we present the crystal structure of the Rpf2–Rrs1 complex from Aspergillus nidulans at 1.5 Å resolution and describe it as Brix domain of Rpf2 completed by Rrs1 to form two anticodon-binding domains with functionally important tails. Fitting the X-ray structure into the cryo-EM density of a previously described pre-60S particle correlates with biochemical data. The heterodimer forms specific contacts with the 5S rRNA, RpL5 and the biogenesis factor Rsa4. The flexible protein tails of Rpf2–Rrs1 localize to the central protuberance. Two helices in the Rrs1 C-terminal tail occupy a strategic position to block the rotation of 25S rRNA and the 5S RNP. Our data provide a structural model for 5S RNP recruitment to the pre-60S particle and explain why removal of Rpf2–Rrs1 is necessary for rearrangements to drive 60S maturation.

The N-terminal extension of yeast ribosomal protein L8 is involved in two major remodeling events during late nuclear stages of 60S ribosomal subunit assembly

“…Interestingly, Rpf2, Rrs1, and Rsa4 form a network that drives formation of the final structure of H89 in rRNA domain V (Kharde et al 2015;Madru et al 2015, Wu et al 2016. Since all of these assembly factors interact with rRNA domain V in the assembling 60S subunit, our results further confirm the role of the N-terminal extension of L8 in structuring domain V (Fig.…”

A Puzzle of Life: Crafting Ribosomal Subunits

“…Formation of the 5S RNP is facilitated by the transport adaptor Syo1, which couples nuclear import of uL5 and uL18 with 5S rRNA association [90,91]. The subsequent incorporation of the 5S RNP module involves the Rpf2-Rrs1 heterodimer and has already occurred within the Nsa1-defined particle [25,86,[92][93][94] (Figure 2K). However, the exact timing and the mechanistic details of the initial 5S RNP docking to the pre-60S ribosome remain to be determined.…”

Fully automatic macromolecular crystallography: the impact of MASSIF-1 on the optimum acquisition and quality of data

“…The energy is fixed at 12.8 keV, allowing de novo structure solution using single wavelength anomalous diffraction (SAD) protocols. [38,47] …”

“…However, these protocols led to the automatic solution of 20 unique structures in 2015. [47,56] While treating all user samples as a whole has led to important developments on the beamline, [40] it can mask the various trends that occur at the level of specific projects. The same analysis is therefore presented for three individual projects that represent different modes of using the beamline (Figure 7(b)-(d)).…”