Correction to: Nature Structural & Molecular Biology https://doi.org/10.1038/s41594-024-01280-z, published online 17 May 2024.

In the version of the article initially published, the text “Composite map showing sCMGE (apix = 1.08 sigma = 0.00828) and additional density observed after particle binning and Pol epsilon signal subtraction (apix = 2.16, sigma = 0.0157)” was missing from the legend to Fig. 2d and has now been added to the HTML and PDF versions of the article.