TABLE 2.

CovR mutants isolated from JRS331 following plating at 40°C

IsolateType of mutation in covRaPredicted consequence of mutation
JRS342R203C (missense)Reduced DNA bindingb
JRS374T192I (missense)Interaction with RNA-polymerase disruptedb
JRS340M1I (missense)No protein made
JRS372W184 (nonsense)cEarly termination
JRS370Y214 (insertion of 1 nucleotide)cEarly termination
JRS376Deletion of 1 nucleotideEarly termination (following amino acid 49)
JRS1806Deletion of 1 nucleotideEarly termination (following amino acid 91)
JRS368Deletion of 356 nucleotidesLacks promoter and first 21 amino acids of CovR
  • a The designations indicate the wild-type amino acid, its position relative to the start codon, and the amino acid resulting from the mutation.

  • b Based on PhoB homology (8).

  • c Termination codon.