1. Centre for Computational Chemistry, School of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
2. School of Biochemistry, University of Bristol, Bristol BS8 1DT, U.K.
3. BrisSynBio Synthetic Biology Research Centre, University of Bristol, Bristol BS8 1TQ, U.K.
4. School of Mathematics and Physics, University of Surrey, Guildford GU2 7XH, U.K.
5. Department of Physics and Astronomy, University of Exeter, Stocker Road, Exeter EX4 4QL, U.K.
6. Institute of Physics and Astronomy, University of Potsdam, Potsdam 14476, Germany