Antibody to sigma 32 cross-reacts with DnaK: association of DnaK protein with Escherichia coli RNA polymerase.

Abstract
A polyclonal antibody to .sigma.32, the heat shock .sigma. factor, has been used to show the presence of low levels of .sigma.32 in Escherichia coli RNA polymerase preparations (E.sigma.70), which explains the observed in vitro activity of E.sigma.70 towards heat shock genes. The .sigma.32 antibody cross-reacts with DnaK, and DnaK has been found associated with purified preparations of both E.sigma.70 and the heat shock RNA polymerase, E.sigma.32.