6rn3

ClpB (DWB mutant) bound to casein in presence of ATPgammaS - state WT-2AClpB (DWB mutant) bound to casein in presence of ATPgammaS - state WT-2A

6rn3, resolution 4.00Å Show:Asymmetric Unit Biological Assembly Structural highlights 6rn3 is a 7 chain structure with sequence from Bos taurus and Escherichia coli HVH 50 (4-2593475). Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 4Å Ligands: Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Publication Abstract from PubMed AAA+ proteins form asymmetric hexameric rings that hydrolyze ATP and thread substrate proteins through a central channel via mobile substrate-binding pore loops. Understanding how ATPase and threading activities are regulated and intertwined is key to understanding the AAA+ protein mechanism. We studied the disaggregase ClpB, which contains tandem ATPase domains (AAA1, AAA2) and shifts between low and high ATPase and threading activities. Coiled-coil M-domains repress ClpB activity by encircling the AAA1 ring. Here, we determine the mechanism of ClpB activation by comparing ATPase mechanisms and cryo-EM structures of ClpB wild-type and a constitutively active ClpB M-domain mutant. We show that ClpB activation reduces ATPase cooperativity and induces a sequential mode of ATP hydrolysis in the AAA2 ring, the main ATPase motor. AAA1 and AAA2 rings do not work synchronously but in alternating cycles. This ensures high grip, enabling substrate threading via a processive, rope-climbing mechanism. Two-Step Activation Mechanism of the ClpB Disaggregase for Sequential Substrate Threading by the Main ATPase Motor.,Deville C, Franke K, Mogk A, Bukau B, Saibil HR Cell Rep. 2019 Jun 18;27(12):3433-3446.e4. doi: 10.1016/j.celrep.2019.05.075. PMID:31216466 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also 3D structures of ClpB