Conformational Dynamics in the Core of Human Y145Stop Prion Protein Amyloid Probed by Relaxation Dispersion NMR

Bacterial MinD and MinE form a standing oscillatory wave which positions the cell division inhibitor MinC, that binds MinD, everywhere on the membrane except at the midpoint of the cell, ensuring midcell positioning of the cytokinetic septum. During this process MinE undergoes fold switching as it interacts with different partners. We explore the exchange dynamics between major and excited states of the MinE dimer in 3 forms using15N relaxation dispersion NMR: the full-length protein (6-stranded β-sheet sandwiched between 4 helices) representing the resting state; a 10-residue N-terminal deletion (Δ10) mimicking the membrane-binding competent state where the N-terminal helix is detached to interact with membrane; and N-terminal deletions of either 30 (Δ30) or 10 residues with an I24N mutation (Δ10/I24N), in which the β1-strands at the dimer interface are extruded and available to bind MinD, leaving behind a 4-stranded β-sheet. Full-length MinE samples 2 “excited” states: The first is similar to a full-length/Δ10 heterodimer; the second, also sampled by Δ10, is either similar to or well along the pathway toward the 4-stranded β-sheet form. Both Δ30 and Δ10/I24N sample 2 excited species: The first may involve destabilization of the β3- and β3′-strands at the dimer interface; changes in the second are more extensive, involving further disruption of secondary structure, possibly representing an ensemble of states on the pathway toward restoration of the resting state. The quantitative information on MinE conformational dynamics involving these excited states is crucial for understanding the oscillation pattern self-organization by MinD–MinE interaction dynamics on the membrane.

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S03A3 Metastable structure detected by relaxation dispersion NMR spectroscopy(Visualising Dynamical Aspects of A Protein Molecule)

Seibutsu Butsuri ◽

10.2142/biophys.47.s4_2 ◽

2007 ◽

Vol 47 (supplement) ◽

pp. S4

Author(s):

Kenji Sugase ◽

Jane H. Dyson ◽

Peter E. Wright

Keyword(s):

Nmr Spectroscopy ◽

Protein Molecule ◽

Relaxation Dispersion ◽

Metastable Structure ◽

Relaxation Dispersion Nmr

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CryoEM and computer simulations reveal a novel kinase conformational switch in bacterial chemotaxis signaling

eLife ◽

10.7554/elife.08419 ◽

2015 ◽

Vol 4 ◽

Cited By ~ 67

Author(s):

C Keith Cassidy ◽

Benjamin A Himes ◽

Frances J Alvarez ◽

Jun Ma ◽

Gongpu Zhao ◽

...

Keyword(s):

Electron Tomography ◽

Conformational Dynamics ◽

Bacterial Chemotaxis ◽

Adaptor Protein ◽

Structural Description ◽

Structural Constraints ◽

The Core ◽

Molecular Events ◽

Density Map ◽

Dynamics Simulations

Chemotactic responses in bacteria require large, highly ordered arrays of sensory proteins to mediate the signal transduction that ultimately controls cell motility. A mechanistic understanding of the molecular events underlying signaling, however, has been hampered by the lack of a high-resolution structural description of the extended array. Here, we report a novel reconstitution of the array, involving the receptor signaling domain, histidine kinase CheA, and adaptor protein CheW, as well as a density map of the core-signaling unit at 11.3 Å resolution, obtained by cryo-electron tomography and sub-tomogram averaging. Extracting key structural constraints from our density map, we computationally construct and refine an atomic model of the core array structure, exposing novel interfaces between the component proteins. Using all-atom molecular dynamics simulations, we further reveal a distinctive conformational change in CheA. Mutagenesis and chemical cross-linking experiments confirm the importance of the conformational dynamics of CheA for chemotactic function.

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