Figure 4.

Swapping of subunits between MsGyr and EcGyr forms active heterotetramers. (A) Schematic representation of the experiment. MsGyrB—blue; MsGyrA—red; EcGyrB—green; EcGyrA—turquoise; (B) Glutaraldehyde crosslinking to show heterotetramer formation by EcGyrA + EcGyrB, MsGyrA + MsGyrB and MsGyrA + EcGyrB and EcGyrA + MsGyrB. The subunits were mixed and incubated on ice for 30 min. Crosslinking reaction with glutaraldehyde (final concentration—0.01%) was carried out at 37°C for 30 min. Native and crosslinked proteins were separated on 8% SDS–PAGE.