Identification of the DNA-binding protein, HrcA, of Streptococcus thermophilus

HrcA a negative transcriptional factor controlling the expression of the st ress-specific operons dnaK and groESL in several bacteria. Although the Hrc A structural gene has been identified in various organisms, studies at the protein level have been so far limited and mostly restricted to Bacillus su btilis. We have identified the HrcA protein of Streptococcus thermophilus a nd show here that it is a dimer with a native molecular mass of 74.5 kDa an d a sequence-specific DNA-binding activity. Partially denatured and inactiv e S. thermophilus HrcA recovered its binding activity in the presence of th e GroEL chaperone. (C) 2001 Published by Elsevier Science B.V. on behalf of the Federation of European Microbiological Societies.