The metabolic state of the mutants is defined by spectroscopic investigations and an in-depth proteomic analysis.
The Fix- mutants were defined by symptoms of nitrogen starvation under symbiotic conditions and the development of small white nodules.
Selection coefficients (s) for the 12 mutants were defined as per-generation percentage reductions or increases in fitness, relative to the parent (wild-type) strain.
The aggregation propensity of SOD1 mutants is defined as the ratio of band intensity of detergent-insoluble versus soluble fractions (P2/S1) (23, 25, 25).
Unique mutants were defined as a distinct combination of amino acids as well as distinct codons across the Cys sites in a mutant block, or mutants with the same combination of codons that were derived from different transformation/selection samples.
Fitness of each deletion mutant is defined by its growth rate during exponential growth relative to wildtype (WT).
In the Finette et al [ 23] study, all but one mutant was defined more completely by sequencing of the base change(s) involved or of the deletion breakpoints.
The same conclusion was drawn differently in [ 13], where the additive neutral mutant is defined as a neutral mutant which lies in the same neutral network as that of the original sequence.
Arbitrary Light Units (ALU) for a given mutant was defined as the decimal logarithm of the maximum value of light produced by this mutant (Light-x) divided by the light produced by the wild type (Light-wt), that is, ALU = log10 (Light-x/Light-wt).
The probability of resistance is the same as the probability to generate mutants, which is defined by the number of cell divisions (and the constant mutation rate).
Among these mutants, 2 were defined by replacements W1170C (C6) and A1187P (P29), which were located very close to the mutated residues detected in this study.
