Polypeptide translocation by the AAA+ ClpXP protease machine.
In the AAA+ ClpXP protease, ClpX uses repeated cycles of ATP hydrolysis to pull native proteins apart and to translocate the denatured polypeptide into ClpP for degradation. Here, we probe polypeptide features important for translocation. ClpXP degrades diverse synthetic peptide substrates despite major differences in side-chain chirality, size, and polarity. Moreover, translocation occurs without a peptide -NH and with 10 methylenes between successive peptide bonds. Pulling on homopolymeric tracts of glycine, proline, and lysine also allows efficient ClpXP degradation of a stably folded protein. Thus, minimal chemical features of a polypeptide chain are sufficient for translocation and protein unfolding by the ClpX machine. These results suggest that the translocation pore of ClpX is highly elastic, allowing interactions with a wide range of chemical groups, a feature likely to be shared by many AAA+ unfoldases.
Barkow
Sarah R
SR
Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
Levchenko
Igor
I
Baker
Tania A
TA
Sauer
Robert T
RT
D000074183:ATPases Associated with Diverse Cellular Activities; D000251:Adenosine Triphosphatases / Q000378:metabolism / Q000502:physiology; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000595:Amino Acid Sequence; D001665:Binding Sites; D049071:Endopeptidase Clp / Q000378:metabolism* / Q000502:physiology; D029968:Escherichia coli Proteins / Q000378:metabolism* / Q000502:physiology; D006868:Hydrolysis; D007700:Kinetics; D018832:Molecular Chaperones / Q000378:metabolism / Q000502:physiology; D010455:Peptides / Q000378:metabolism*; D011485:Protein Binding; D017510:Protein Folding; D013379:Substrate Specificity
D029968:Escherichia coli Proteins; D018832:Molecular Chaperones; D010455:Peptides; D000255:Adenosine Triphosphate; C483572:ClpP protease, E coli; C483573:ClpXP protease, E coli; D049071:Endopeptidase Clp; D000251:Adenosine Triphosphatases; C088072:ClpX protein, E coli; D000074183:ATPases Associated with Diverse Cellular Activities