Fig. 2

Key substructure difference between Class I and II compounds identified using the rule induction algorithm OneR. Two Class I compounds (chloroquine and apicidin) and two Class II compounds (MMS and cerulenin) are shown as an example. The substructures are numbered from 0 to 880, with the position of a given substructure referred to as its bit position. The bit structure represents a chemical element, group, ring structure or atom pairs based on the PubChem substructure fingerprints. The presence of a given substructure is encoded by 1 and the absence by a 0. Class I and II compounds are largely differentiated at bit position 185 which encodes the substructure fingerprint ‘≥2 any ring size 6’