TABLE 5

Base-substitution rates (μb) for mutant RB69 DNA polymerases without and with accessory proteins

Pol+ Exo-PolM Exo+PolM Exo-
Template•primer
mispair (opportunities)a
No.μbNo.μbNo.μb
-AP+AP-AP+AP-AP+AP-AP+AP-AP+AP-AP+AP
All (128)9313717191101094768120153160278
A•dCTP (19)1414206400≤9≤12
T•dGTP (28)1324111676721502003768230570
G•dTTP (22)889771518545456420590
C•dATP (25)455842421783825122182200
A•dGTP (17)111100≤3≤51010≤14
A•dATP (23)16152153211510
G•dGTP (20)7108922684034≤12
G•dATP (25)157145152162014≤9
T•dTTP (16)06≤1723715838544
T•dCTP (23)05≤1403≤21001≤710
C•dTTP (17)1616103≤503≤1041
C•dCTP (9)123400≤6≤900≤20≤26
  • The mutation rates in Table 1 and summary sequence data in Table 2 were used to calculate mutation rates (μb) that are rounded to reflect the numbers of observed mutations. Because the wild-type polymerase did not generate errors above the historical background mutant frequency of uncopied DNA, its mutant frequency of 6.2 × 10-4 was subtracted from each mutator-polymerase frequency. Mutation rates are per 106 nucleotides incorporated and were calculated by multiplying the net mutant frequency (Table 1) by the proportion of mutants in each class (Table 2) and dividing by 0.6 (the correction factor for detecting errors in E. coli) and by the number of detectable sites (“opportunities”) for each class of mutation (see materials and methods, Sequencing). “≤” values were calculated as if one mutant had been detected.

  • a The number of detectable events is unambiguously defined for the specific mispairs. From 1 to 3 substitutions are detectable at 128 sites, a value we used for comparison with other published values. However, there are only 244 possible substitutions at these 128 sites, and careful readers could recalculate the rates normalized to this value.