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Table 1 Ciprofloxacin susceptibility of QnrC and QnrA1 mutants.

From: A mutational analysis and molecular dynamics simulation of quinolone resistance proteins QnrA1 and QnrC from Proteus mirabilis

Groups/clusters Mutagenesis and codon alteration a Position of mutation Qnr protein MIC (μg ml-1)
  pHSG398 - - 0.002
Control pHS12 wild type QnrC 0.125
  pMG252-1 wild type QnrA1 0.125
  L38R(TTA→AGA) i QnrC 0.003
  L38A(TTA→GCA) i QnrC 0.125
Hydrophobic interior of β-helix L38F(CTG→TTC) i QnrA1 0.125
  F13S(TTC→TCC)c i QnrA1 0.008
  C72Y(TGC→TAC) or A97Y(GCT→TAT) i-2 QnrC 0.003
  S116P (TCT→CCT) c i+2 QnrC 0.002
Constraint effect of Pro to the backbone S153P(TCT→CCT)c i-1 QnrC 0.003
  L38P(CTG→CCG)c i QnrA1 0.004
  C84S(TGT→TCT) i QnrC 0.094
  C84S(TGC→AGC) i QnrA1 0.064
Cys to Ser mutation C31 S or C36 S or C57 S or C177 S (TGT→AGT);
C26 S or C46 S or C72 S or C92 S or C122 S or C137S(TGC→AGC)
i-2 QnrA1 0.125
  C133S(TGC→AGC)or C168S(TGT→AGT) i-1 QnrA1 0.125
  C115S(TGC→AGC)or C200S(TGT→AGT) i+1 QnrA1 0.125
  Δ11-20 N-terminus QnrC 0.003
  Δ2-21 N-terminus QnrA1 0.002
  Δ2-10 N-terminus QnrA1 0.003
  Δ49-55 G56 region QnrC 0.003
Fragment truncation b Δ41-56, Δ51-56 G56 region QnrA1 0.003
  Δ77-96, Δ137-156 β-helix backbone QnrC 0.003
  Δ216-218 C-terminus QnrC 0.064
  Δ187-218 C-terminus QnrA1 0.003
  Δ207-218 C-terminus QnrA1 0.004
  D188V (GAC→GTC)c i+1 QnrA1 0.003
Others M44T(ATG→ACG) i+1 QnrC 0.125
  I216T (ATT→ACT) c i+2 QnrC 0.125
  E50A(GAA→GCC) or E50G (GAA→GGC) or E55A (GAA→GCT) or E55G(GAA→GGA) i+2 QnrA1 0.125
  1. a nucleotide substitution is in parentheses
  2. b Δ2-21 indicates deletion of amino acids 2-21
  3. c mutations were obtained by random mutagenesis and confirmed by site-directed mutagenesis