1ox9
From Proteopedia
Crystal structure of SspB-ssrA complex
Overview
In prokaryotes, incomplete or misfolded polypeptides emanating from a stalled ribosome are marked for degradation by the addition of an 11 residue peptide (AANDENYALAA) to their C terminus. Substrates containing this conserved degradation signal, the SsrA tag, are targeted to specific proteases including ClpXP and ClpAP. SspB was originally characterized as a stringent starvation protein and has been found to bind specifically to SsrA-tagged proteins and to enhance recognition of these proteins by the ClpXP degradation machine. Here, we report the crystal structures of SspB alone and in complex with an SsrA peptide. Unexpectedly, SspB exhibits a fold found in Sm-family RNA binding proteins. The dimeric SspB structures explain the key determinants for recognition of the SsrA tag and define a hydrophobic channel that may bind unfolded substrates.
About this Structure
1OX9 is a Single protein structure of sequence from Escherichia coli o157:h7. Full crystallographic information is available from OCA.
Reference
Structural basis of degradation signal recognition by SspB, a specificity-enhancing factor for the ClpXP proteolytic machine., Song HK, Eck MJ, Mol Cell. 2003 Jul;12(1):75-86. PMID:12887894 Page seeded by OCA on Sat May 3 04:23:23 2008
