Download MendeleyStructural analysis of the dodecameric proteasome activator PafE in Mycobacterium tuberculosis.
Bai, L., Hu, K., Wang, T., Jastrab, J.B., Darwin, K.H., Li, H.(2016) Proc Natl Acad Sci U S A 113: E1983-E1992
- PubMed: 27001842
- DOI: https://doi.org/10.1073/pnas.1512094113
- Primary Citation of Related Structures:
5IET, 5IEU - PubMed Abstract:
The human pathogen Mycobacterium tuberculosis (Mtb) requires a proteasome system to cause lethal infections in mice. We recently found that proteasome accessory factor E (PafE, Rv3780) activates proteolysis by the Mtb proteasome independently of adenosine triphosphate (ATP). Moreover, PafE contributes to the heat-shock response and virulence of Mtb Here, we show that PafE subunits formed four-helix bundles similar to those of the eukaryotic ATP-independent proteasome activator subunits of PA26 and PA28. However, unlike any other known proteasome activator, PafE formed dodecamers with 12-fold symmetry, which required a glycine-XXX-glycine-XXX-glycine motif that is not found in previously described activators. Intriguingly, the truncation of the PafE carboxyl-terminus resulted in the robust binding of PafE rings to native proteasome core particles and substantially increased proteasomal activity, suggesting that the extended carboxyl-terminus of this cofactor confers suboptimal binding to the proteasome core particle. Collectively, our data show that proteasomal activation is not limited to hexameric ATPases in bacteria.
Organizational Affiliation:
Biosciences Department, Brookhaven National Laboratory, Upton, NY 11973;
