Electronic properties of chlorofuranones including MX, one of the stro
ngest bacterial mutagens, were studied using the semi-empirical AM1 me
thod to elucidate the key features related to the high mutagenic activ
ity of MX. The electronic structures of MX and guanine (the target bas
e of the Salmonella typhimurium TA100 tester strain) are rationalized
with the frontier electron theory. Hydrophobic properties of the MX fa
mily are examined. Based on these results and our previous QSAR model
a possible mechanism for the MX-DNA interaction is proposed.