1OU9

Structure of SspB, a AAA+ protease delivery protein

Summary for 1OU9

• Entry DOI: 10.2210/pdb1ou9/pdb
• Related: 1OU8 1OUL
• Descriptor: Stringent starvation protein B homolog, CALCIUM ION (3 entities in total)
• Functional Keywords: ssra peptide-binding protein, homodimer, transport protein
• Biological source: Haemophilus influenzae
• Total number of polymer chains: 3
• Total formula weight: 44483.16

Authors

Levchenko, I.,Grant, R.A.,Wah, D.A.,Sauer, R.T.,Baker, T.A. (deposition date: 2003-03-24, release date: 2003-09-23, Last modification date: 2014-04-30)

Primary citation

Levchenko, I.,Grant, R.A.,Wah, D.A.,Sauer, R.T.,Baker, T.A.
Structure of a delivery protein for an AAA+ protease in complex with a peptide degradation tag
Mol.Cell, 12:365-372, 2003

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.

PubMed: 14536076
DOI: 10.1016/j.molcel.2003.08.014

Experimental method

X-RAY DIFFRACTION (1.8 Å)