A structural insight into the prokaryotic heat shock transcription regulatory protein σ(32): an implication of σ(32)-DnaK interaction

The heat shock response mechanism is a very vital biochemical process and is mainly controlled by σ(32) protein. The function of σ(32) is temperature dependent and at lower temperatures σ(32) is inactivated by its interactions with DnaK. This interaction is completely abolished above 42°C till date no molecular details of the interactions are available. In the present scenario, an attempt has been made to analyze first the predicted structure of σ(32) obtained by comparative modeling techniques and then to study the interactions between σ(32) and DnaK. From this molecular modeling study we could specifically identify the binding sites of the interactions of σ(32) with DnaK which will enlighten the mechanism of regulation of its activity and stability by DnaK. Our study provides the idea for future mutational experiments in order to find out the possible roles of the amino acids of region2 and region3 of σ(32) in stability as well as in binding with DnaK.