The activity of this thermoregulator was confirmed in vitro but was not found in vivo, suggesting more complicated operon regulation exists in bacterial cells.

When IbpB is absent, IbpA protein will form long fibrils which is unusual for a heat shock protein; IbpB, acting as a co-chaperone, inhibits IbpA from forming this structure.

[5] Under heat shock, IbpB protein dissociates to give two smaller subunits and also rearranges its tertiary structure.

[6] This "remarkable conformational transformation"[7] is thought to be essential for IbpB to act as a co-chaperone with IbpA under heat shock.

[8] IbpB has been found to retain active for a significant time after a heat shock stimulus has been removed.