1. The Francis Crick Institute; 1 Midland road London NW1 1AT UK
2. Sorbonne Universités, UPMC Univ Paris 06, ENS, CNRS; Laboratoire des Biomolécules (LBM); Paris France
3. Département de Chimie, ENS; PSL Research University, UPMC, Univ Paris 06, CNRS, LBM; Paris France
4. Merck Chemicals; Padge Road, Beeston Notts NG9 2JR UK