1. Chemistry Research Laboratory, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
2. Department of Chemistry and Warwick Integrative Synthetic Biology Centre, University of Warwick, Coventry, CV4 7AL, UK
3. Department of Biochemistry and Molecular Biology and ARC Centre of Excellence for Innovations in Peptide and Protein Science, Biomedicine Discovery Institute, Monash University, Clayton, Victoria 3800, Australia