Correction to: Nature Structural & Molecular Biology Published online 16 May 2022.

In the version of this article initially published, reference 74 was a duplicate of reference 34 (Wargo, M. J. & Smith, E. F. Proc. Natl Acad. Sci. USA 100, 137–142 (2003)); the reference cited twice as 74 in the caption for Extended Data Fig. 10 should have been Leung, M. R. et al. EMBO J. 40, e107410 (2021). The citations and reference list have been corrected in the HTML and PDF versions of the article.