Pore loops of the AAA+ ClpX machine grip substrates to drive translocation and unfolding. Export

@article{citeulike:3442581, abstract = {Proteolytic AAA+ unfoldases use ATP hydrolysis to power conformational changes that mechanically denature protein substrates and then translocate the polypeptide through a narrow pore into a degradation chamber. We show that a tyrosine residue in a pore loop of the hexameric ClpX unfoldase links ATP hydrolysis to mechanical work by gripping substrates during unfolding and translocation. Removal of the aromatic ring in even a few ClpX subunits results in slippage, frequent failure to denature the substrate and an enormous increase in the energetic cost of substrate unfolding. The tyrosine residue is part of a conserved aromatic-hydrophobic motif, and the effects of mutations in both residues vary with the nucleotide state of the resident subunit. These results support a model in which nucleotide-dependent conformational changes in these pore loops drive substrate translocation and unfolding, with the aromatic ring transmitting force to the polypeptide substrate.}, author = {Martin, Andreas and Baker, Tania A A. and Sauer, Robert T T.}, citeulike-article-id = {3442581}, citeulike-linkout-0 = {http://dx.doi.org/10.1038/nsmb.1503}, citeulike-linkout-1 = {http://view.ncbi.nlm.nih.gov/pubmed/18931677}, citeulike-linkout-2 = {http://www.hubmed.org/display.cgi?uids=18931677}, day = {19}, doi = {10.1038/nsmb.1503}, issn = {1545-9985}, journal = {Nature structural \& molecular biology}, keywords = {aaa, clipx}, month = {October}, posted-at = {2008-10-23 12:18:10}, priority = {2}, title = {Pore loops of the AAA+ ClpX machine grip substrates to drive translocation and unfolding.}, url = {http://dx.doi.org/10.1038/nsmb.1503}, year = {2008} }

TY - JOUR ID - citeulike:3442581 L3 - citeulike-article-id:3442581 N2 - Proteolytic AAA+ unfoldases use ATP hydrolysis to power conformational changes that mechanically denature protein substrates and then translocate the polypeptide through a narrow pore into a degradation chamber. We show that a tyrosine residue in a pore loop of the hexameric ClpX unfoldase links ATP hydrolysis to mechanical work by gripping substrates during unfolding and translocation. Removal of the aromatic ring in even a few ClpX subunits results in slippage, frequent failure to denature the substrate and an enormous increase in the energetic cost of substrate unfolding. The tyrosine residue is part of a conserved aromatic-hydrophobic motif, and the effects of mutations in both residues vary with the nucleotide state of the resident subunit. These results support a model in which nucleotide-dependent conformational changes in these pore loops drive substrate translocation and unfolding, with the aromatic ring transmitting force to the polypeptide substrate. JF - Nature structural & molecular biology SN - 1545-9985 TI - Pore loops of the AAA+ ClpX machine grip substrates to drive translocation and unfolding. KW - aaa KW - clipx AU - Martin, Andreas AU - Baker, Tania A AU - Sauer, Robert T PY - 2008/10/19/ UR - http://dx.doi.org/10.1038/nsmb.1503 ER -