1 Bishop Wardlaw Professor of Chemical Biology, Royal Society Wolfson Research Merit Award Holder, BSRC, The North Haugh, The University, St Andrews KY16 9ST, UK. Electronic address: naismith@st-andrews.ac.uk.
2 Department of Chemistry, University of Canterbury, Private Bag 4800, Christchurch, New Zealand. Electronic address: emily.parker@canterbury.ac.nz.