7rak

Methanococcus maripaludis chaperonin complex in open conformation

spinqualitylabelsall models 7rak, resolution 3.90Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 7rak is a 16 chain structure with sequence from Methanococcus maripaludis. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Ligands: ATP Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function Q877G8_METMI Publication Abstract from PubMed Chaperonins are homo- or hetero-oligomeric complexes that use ATP binding and hydrolysis to facilitate protein folding. ATP hydrolysis exhibits both positive and negative cooperativity. The mechanism by which chaperonins coordinate ATP utilization in their multiple subunits remains unclear. Here we use cryoEM to study ATP binding in the homo-oligomeric archaeal chaperonin from Methanococcus maripaludis (MmCpn), consisting of two stacked rings composed of eight identical subunits each. Using a series of image classification steps, we obtained different structural snapshots of individual chaperonins undergoing the nucleotide binding process. We identified nucleotide-bound and free states of individual subunits in each chaperonin, allowing us to determine the ATP occupancy state of each MmCpn particle. We observe distinctive tertiary and quaternary structures reflecting variations in nucleotide occupancy and subunit conformations in each chaperonin complex. Detailed analysis of the nucleotide distribution in each MmCpn complex indicates that individual ATP binding events occur in a statistically random manner for MmCpn, both within and across the rings. Our findings illustrate the power of cryoEM to characterize a biochemical property of multi-subunit ligand binding cooperativity at the individual particle level. CryoEM reveals the stochastic nature of individual ATP binding events in a group II chaperonin.,Zhao Y, Schmid MF, Frydman J, Chiu W Nat Commun. 2021 Aug 6;12(1):4754. doi: 10.1038/s41467-021-25099-0. PMID:34362932 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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