Structure of a delivery protein for an AAA+ protease in complex with a peptide degradation tagLevchenko, I., Grant, R.A., Wah, D.A., Sauer, R.T., Baker, T.A.
(2003) Mol Cell 12: 365-372
- PubMed: 14536076
- DOI: https://doi.org/10.1016/j.molcel.2003.08.014
- Primary Citation of Related Structures:
1OU8, 1OU9, 1OUL
- PubMed Abstract:
Substrate selection by AAA+ ATPases that function to unfold proteins or alter protein conformation is often regulated by delivery or adaptor proteins. SspB is a protein dimer that binds to the ssrA degradation tag and delivers proteins bearing this tag to ClpXP, an AAA+ protease, for degradation. Here, we describe the structure of the peptide binding domain of H. influenzae SspB in complex with an ssrA peptide at 1.6 A resolution. The ssrA peptides are bound in well-defined clefts located at the extreme ends of the SspB homodimer. SspB contacts residues within the N-terminal and central regions of the 11 residue ssrA tag but leaves the C-terminal residues exposed and positioned to dock with ClpX. This structure, taken together with biochemical analysis of SspB, suggests mechanisms by which proteins like SspB escort substrates to AAA+ ATPases and enhance the specificity and affinity of target recognition.
Howard Hughes Medical Institute, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.