TY - JOUR
T1 - Bypassing fluoroquinolone resistance with quinazolinediones
T2 - Studies of drug-gyrase-DNA complexes having implications for drug design
AU - Drlica, Karl
AU - Mustaev, Arkady
AU - Towle, Tyrell R.
AU - Luan, Gan
AU - Kerns, Robert J.
AU - Berger, James M.
N1 - Publisher Copyright:
© 2014 American Chemical Society.
PY - 2014/12/19
Y1 - 2014/12/19
N2 - Widespread fluoroquinolone resistance has drawn attention to quinazolinediones (diones), fluoroquinolone-like topoisomerase poisons that are unaffected by common quinolone-resistance mutations. To better understand differences between quinolones and diones, we examined their impact on the formation of cleaved complexes (drug-topoisomerase-DNA complexes in which the DNA moiety is broken) with gyrase, one of two bacterial targets of the drugs. Formation of cleaved complexes, measured by linearization of a circular DNA substrate, required lower concentrations of quinolone than dione. The reverse reaction, detected as resealing of DNA breaks in cleaved complexes, required higher temperatures and EDTA concentrations for quinolones than diones. The greater stability of quinolone-containing complexes was attributed to the unique ability of the quinolone C3/C4 keto acid to complex with magnesium and form a previously described drug-magnesium-water bridge with GyrA-Ser83 and GyrA-Asp87. A nearby substitution in GyrA (G81C) reduced activity differences between quinolone and dione, indicating that resistance due to this variation derives from perturbation of the magnesium-water bridge. To increase dione activity, we examined a relatively small, flexible C-7-3-(aminomethyl)pyrrolidinyl substituent, which is distal to the bridging C3/C4 keto acid substituent of quinolones. The 3-(aminomethyl)pyrrolidinyl group at position C-7 was capable of forming binding interactions with GyrB-Glu466, as indicated by inspection of crystal structures, computer-aided docking, and measurement of cleaved-complex formation with mutant and wild-type GyrB proteins. Thus, modification of dione C-7 substituents constitutes a strategy for obtaining compounds active against common quinolone-resistant mutants.
AB - Widespread fluoroquinolone resistance has drawn attention to quinazolinediones (diones), fluoroquinolone-like topoisomerase poisons that are unaffected by common quinolone-resistance mutations. To better understand differences between quinolones and diones, we examined their impact on the formation of cleaved complexes (drug-topoisomerase-DNA complexes in which the DNA moiety is broken) with gyrase, one of two bacterial targets of the drugs. Formation of cleaved complexes, measured by linearization of a circular DNA substrate, required lower concentrations of quinolone than dione. The reverse reaction, detected as resealing of DNA breaks in cleaved complexes, required higher temperatures and EDTA concentrations for quinolones than diones. The greater stability of quinolone-containing complexes was attributed to the unique ability of the quinolone C3/C4 keto acid to complex with magnesium and form a previously described drug-magnesium-water bridge with GyrA-Ser83 and GyrA-Asp87. A nearby substitution in GyrA (G81C) reduced activity differences between quinolone and dione, indicating that resistance due to this variation derives from perturbation of the magnesium-water bridge. To increase dione activity, we examined a relatively small, flexible C-7-3-(aminomethyl)pyrrolidinyl substituent, which is distal to the bridging C3/C4 keto acid substituent of quinolones. The 3-(aminomethyl)pyrrolidinyl group at position C-7 was capable of forming binding interactions with GyrB-Glu466, as indicated by inspection of crystal structures, computer-aided docking, and measurement of cleaved-complex formation with mutant and wild-type GyrB proteins. Thus, modification of dione C-7 substituents constitutes a strategy for obtaining compounds active against common quinolone-resistant mutants.
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U2 - 10.1021/cb500629k
DO - 10.1021/cb500629k
M3 - Article
C2 - 25310082
AN - SCOPUS:84919629271
SN - 1554-8929
VL - 9
SP - 2895
EP - 2904
JO - ACS Chemical Biology
JF - ACS Chemical Biology
IS - 12
ER -