Correction to: Communications Biology https://doi.org/10.1038/s42003-019-0604-2, published online 4 October 2019.

In the original version of the published article, the caption to Figure 2e contained the following text that incorrectly referenced ExbB and an incorrect PDB code: “Ribbon representation of the solution structure of the ExbB soluble periplasmic domain (in green, pdb code 2PDU)4 and ExbB–ExbD”.

This has been replaced with the following corrected text: “Ribbon representation of the solution structure of the ExbD soluble periplasmic domain (in green, pdb code 2PFU)4 and ExbB–ExbD”. The error has been corrected in the HTML and PDF versions of the article.