Bacterial Proteasome Activator Bpa (Rv3780) Is a Novel Ring-Shaped Interactor of the Mycobacterial Proteasome
Figure 4
Bpa can be retained by immobilized Δ7PrcAB or half-proteasomes.
A, Elution fractions of the pull-downs of Bpa or BpaΔHbYX with different Strep-immobilized proteasome particles. Strep-tagged proteasome particles were eluted from Strep-Tactin Sepharose with 2.5 mM desthiobiotin and the elution fractions were visualized on Coomassie stained SDS-PAGE. Bpa binds to Δ7PrcAB, while BpaΔHbYX does not. PrcAB interaction with Bpa is not detectable, while half-proteasomes (proPrcAB) retain a small amount of Bpa. B, Maturation of half-proteasomes at 37°C for 24 hours followed by SDS-PAGE. No difference in processing speed can be observed in the reactions supplemented with Bpa compared to PrcAB alone within this time frame.