Rotating Frame Relaxation in Magic Angle Spinning Solid State NMR, a Promising Tool for Characterizing Biopolymer Motion

Keeler, Eric G.; McDermott, Ann E.

doi:10.1021/acs.chemrev.2c00442

Cited by 7 publications

(8 citation statements)

References 48 publications

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“…Under MAS, 15 N R 1ρ rates depend on the spectral densities J (ω) at the sum and difference frequencies of the spin-lock field strengths ω 1 and MAS frequency ω r . ,,,, For ω 1 /2π values of 2–12.5 kHz and ω r /2π of 55 kHz, motions with rates of 55–132 × 10 3 s –1 modulate the 15 N- 1 H dipolar coupling and 15 N chemical shift anisotropy (CSA) to cause R 1ρ relaxation. Therefore, the 15 N R 1ρ rates measured under our experimental conditions are sensitive to motions on the timescale of 8–18 μs.…”

Section: Resultssupporting

confidence: 59%

“…Under MAS, 15 N R 1ρ rates depend on the spectral densities J (ω) at the sum and difference frequencies of the spin-lock field strengths ω 1 and MAS frequency ω r . ,,,, R 1 ρ , NH = 1 20 true[ μ 0 4 π ℏ γ normalH γ normalN r NH 3 0.25em true] 2 true[ 2 3 ( J false( ω 1 + 2 ω r false) + J false( ω 1 − 2 ω r false) ) + 4 3 0.25em ( J false( ω 1 + ω r false) + J false( ω 1 − ω r false) ) + 0.25em 3 J ( ω N ) + J ( …”

Section: Resultsmentioning

confidence: 99%

“…Under MAS, 15 N R 1ρ rates depend on the spectral densities J(ω) at the sum and difference frequencies of the spin-lock field strengths ω 1 and MAS frequency ω r . 26,28,37,46,47 = +…”

Section: ■ Resultsmentioning

confidence: 99%

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Microsecond Motion of the Bacterial Transporter EmrE in Lipid Bilayers

et al. 2023

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The bacterial transporter EmrE is a homo-dimeric membrane protein that effluxes cationic polyaromatic substrates against the concentration gradient by coupling to proton transport. As the archetype of the small multidrug resistance family of transporters, EmrE structure and dynamics provide atomic insights into the mechanism of transport by this family of proteins. We recently determined high-resolution structures of EmrE in complex with a cationic substrate, tetra(4-fluorophenyl)phosphonium (F 4 -TPP + ), using solid-state NMR spectroscopy and an S64V-EmrE mutant. The substrate-bound protein exhibits distinct structures at acidic and basic pH, reflecting changes upon binding or release of a proton from residue E14, respectively. To obtain insight into the protein dynamics that mediate substrate transport, here we measure 15 N rotating-frame spin-lattice relaxation (R 1ρ ) rates of F 4 -TPP + -bound S64V-EmrE in lipid bilayers under magic-angle spinning (MAS). Using perdeuterated and back-exchanged protein and 1 H-detected 15 N spin-lock experiments under 55 kHz MAS, we measured 15 N R 1ρ rates site-specifically. Many residues show spin-lock field-dependent 15 N R 1ρ relaxation rates. This relaxation dispersion indicates the presence of backbone motions at a rate of about 6000 s −1 at 280 K for the protein at both acidic and basic pH. This motional rate is 3 orders of magnitude faster than the alternating access rate but is within the range estimated for substrate binding. We propose that these microsecond motions may allow EmrE to sample different conformations to facilitate substrate binding and release from the transport pore.

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Section: Resultssupporting

confidence: 59%

Section: Resultsmentioning

confidence: 99%

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Microsecond Motion of the Bacterial Transporter EmrE in Lipid Bilayers

et al. 2023

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Section: Resultsmentioning

confidence: 99%

Disulfide-bond-induced structural frustration and dynamic disorder in a peroxiredoxin from MAS NMR

Troussicot

Vallet

Molin

et al. 2023

Preprint

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Disulfide bond formation is fundamentally important for protein structure, and constitutes a key mechanism by which cells regulate the intracellular oxidation state. Peroxiredoxins (PRDXs) eliminate reactive oxygen species such as hydrogen peroxide by using a catalytic cycle of Cys oxidation and reduction. High molecular-weight assemblies of PRDXs have recently been shown to additionally act as molecular chaperones. The consequences of disulfide bonds on the dynamics of these large assemblies are poorly understood. We show that formation of disulfide bonds along the catalytic cycle induces extensive μs time scale dynamics, as monitored by magic-angle spinning NMR of the 216 kDa-large Tsa1 decameric assembly and solution-NMR of a designed dimeric mutant. We ascribe the conformational dynamics to structural frustration, result- ing from conflicts between the disulfide-constrained reduction of mobility and the desire to fulfill other favorable contacts.

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“…Longitudinal relaxation ( R 1 ) is sensitive mostly to amplitudes and time scales of motions occurring on ps-ns time scales. Relaxation of 15 N coherence in the presence of a spin-lock pulse ( R 1ρ ) is mostly sensitive to motions on time scales of tens of nanoseconds to hundreds of μs. − Figure A, B shows calculated relaxation rate constants for motion occurring on different time scales. R 1ρ experiments can be applied at multiple radiofrequency (RF) spin-lock field strengths, and the dependence on the RF field strength reveals specifically μs–ms motion (Figure A, insert), an effect sometimes referred to as NEar Rotary-resonance Relaxation Dispersion (NERRD; see below). ,, Thus, these different relaxation measurements allow the identification and quantitative interpretation of motional time scales and amplitudes in different time windows.…”

Section: Results and Discussionmentioning

confidence: 99%

Disulfide-Bond-Induced Structural Frustration and Dynamic Disorder in a Peroxiredoxin from MAS NMR

et al. 2023

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Disulfide bond formation is fundamentally important for protein structure and constitutes a key mechanism by which cells regulate the intracellular oxidation state. Peroxiredoxins (PRDXs) eliminate reactive oxygen species such as hydrogen peroxide through a catalytic cycle of Cys oxidation and reduction. Additionally, upon Cys oxidation PRDXs undergo extensive conformational rearrangements that may underlie their presently structurally poorly defined functions as molecular chaperones. Rearrangements include high molecular-weight oligomerization, the dynamics of which are, however, poorly understood, as is the impact of disulfide bond formation on these properties. Here we show that formation of disulfide bonds along the catalytic cycle induces extensive μs time scale dynamics, as monitored by magic-angle spinning NMR of the 216 kDa-large Tsa1 decameric assembly and solution-NMR of a designed dimeric mutant. We ascribe the conformational dynamics to structural frustration, resulting from conflicts between the disulfide-constrained reduction of mobility and the desire to fulfill other favorable contacts.

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Rotating Frame Relaxation in Magic Angle Spinning Solid State NMR, a Promising Tool for Characterizing Biopolymer Motion

Cited by 7 publications

References 48 publications

Microsecond Motion of the Bacterial Transporter EmrE in Lipid Bilayers

Microsecond Motion of the Bacterial Transporter EmrE in Lipid Bilayers

Disulfide-bond-induced structural frustration and dynamic disorder in a peroxiredoxin from MAS NMR

Disulfide-Bond-Induced Structural Frustration and Dynamic Disorder in a Peroxiredoxin from MAS NMR

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