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. Author manuscript; available in PMC: 2014 Jun 27.
Published in final edited form as: DNA Repair (Amst). 2008 Aug 29;7(10):1731–1745. doi: 10.1016/j.dnarep.2008.06.019

Figure 3. Amino acid substitutions in unselected and selected AAG mutants.

Figure 3

A, Conservation of AAG primary sequence in natural evolution. Aligned sequences of human AAG and homologs are shown; numbering refers to the human sequence. Absolutely conserved residues are indicated in dark gray and the numbers are boxed. Residues showing only conservative substitutions are indicated in light gray and the numbers are underlined. B-E, Plasmid libraries harboring mutant AAGs created by random mutagenesis were expressed in glycosylase-deficient E. coli MV1932. Mutants that complemented the methylating agent sensitivity of MV1932 cells were selected and the plasmid sequences were determined. Amino acid substitutions shown were observed in 72 mutants from the unselected AAG SK and KX libraries (B), 89 single mutants selected for MMS resistance (C), 25 double mutants selected for MMS resistance (D), and 42 mutants selected for Me-lex resistance (E). Mutations in 4 MMS-resistant triple mutants are not shown.