Evidence that the recA441 (tif-1) mutant of Escherichia coli K-12 contains a thermosensitive intragenic suppressor of RecA constitutive protease activity.

The recA441 mutant of Escherichia coli, which has been thought to have thermoinducible constitutive RecA protease activity, is known to have two mutations within recA. We show here that the mutation that alters codon 38 actually confers temperature-independent constitutive protease activity; the second mutation in recA441, which is at codon 298, appears to be acting as a temperature-sensitive suppressor of the protease activity.