We thank R. Grassucci, D. Bobe, K. Jordan, L. Yen, A. Raczkowski, W. Rice, E. Eng, M. Kopylov, and B. Carragher for access to the electron microscopy facility and help with data collection at the New York Structural Biology Center; and R. Grassucci and Z. Fu for help with data collection at the EM facility at Columbia University. We thank S. Qian and X. Qiang (Pharmaron) for enzyme-activity assay and kinetics studies, M. Geitman (Beactica) for SPR studies, D. Lakshminarasimhan (Xtal BioStructures) for structural studies on the N-terminal segment, proteolysis and early DSF work, Pharmaron for small-molecule synthesis, and H. Blanchette and K. Kreutter (Nimbus) for discussions. The portion of this research that was conducted in the L.T. laboratory was supported by a grant from Nimbus. Some of this work was performed at the Simons Electron Microscopy Center and National Resource for Automated Molecular Microscopy located at the New York Structural Biology Center, supported by grants from the Simons Foundation (349247), NYSTAR, and the NIH National Institute of General Medical Sciences (GM103310).

Reviewer information

Nature thanks Frank M. Raushel and the other anonymous reviewer(s) for their contribution to the peer review of this work.