Time-resolved infrared studies of the unfolding of a light triggered β-hairpin peptide

Rampp, Michael S.; Hofmann, Stefan; Podewin, Tom; Hoffmann‐Röder, Anja; Moröder, Luis

doi:10.1016/j.chemphys.2018.02.003

Cited by 13 publications

(13 citation statements)

References 39 publications

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“…Time-resolved experiments have demonstrated that the folding and unfolding of this hairpin occurred on the 20 μs time scale. 15 In addition, we recently presented a photo-switchable derivative of the stable β-hairpin forming peptide chignolin (GYDPETGTWG) 42 in which AMPP 41 replaces two central amino acids (E5 and T6) of the loop. 43 This peptide AzoChignolin is shorter than the photoswitchable Azo-TrpZip hairpin and contains only two amino acids with large hydrophobic aromatic side chains instead of the four tryptophan residues found in Azo-TrpZip.…”

Section: ■ Introductionmentioning

confidence: 99%

“…Various experimental techniques have been introduced to characterize the dynamics of the folding process and provide information on the molecular structure as a function of time . Here, time-resolved IR spectroscopy has proven to be an important and structure-sensitive tool. − For such a time-resolved investigation, the folding process must be synchronized with the detection process. Initiation of the folding events must be performed with temporal precision that is sufficient to map the underlying structural dynamics, for example, by using short light pulses that trigger the structural change via a molecular switch.…”

Section: Introductionmentioning

confidence: 99%

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Folding and Unfolding of the Short Light-Triggered β-Hairpin Peptide AzoChignolin Occurs within 100 ns

et al. 2020

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To map the underlying molecular mechanisms of folding dynamics in proteins, light-operated peptides have emerged as promising tools. In this study, we reveal the complete sequence of light-induced structural changes of AzoChignolin, a short β-hairpin peptide containing an azobenzene photoswitch in its loop region. Light-triggered structural changes were monitored by time-resolved IR spectroscopy. Formation and destruction of the hairpin structure is very fast and occurs within 100 ns for AzoChignolin in methanol. Atomistic molecular dynamics simulations using two explicit solvents, methanol and water, revealed the underlying molecular processes and allowed us to gain further insight into the reaction mechanism. Despite its rapid reaction time, hairpin formation in these solvents is not force-driven by the molecular switch but proceeded via formation of interstrand hydrogen bonds and contacts between aromatic residues. Moreover, the combined experimental and theoretical study demonstrates that the solvent (methanol vs water) does not dictate the velocity of β-hairpin formation in the AzoChignolin peptide comprising only a few hydrophobic residues in the strands.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Folding and Unfolding of the Short Light-Triggered β-Hairpin Peptide AzoChignolin Occurs within 100 ns

et al. 2020

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“…The process can be easily monitored looking at the absorption spectrum of azobenzene itself, that is strongly different in the two forms, trans and cis (Schultz et al, 2003; Satzger et al, 2004; Quick et al, 2014). In particular, the AMPP chromophore incorporation in a peptide sequence led to a β-hairpin structure after irradiation (Dong et al, 2006, 2017; Rampp et al, 2018), and the AMPB was described as a trigger molecule in cyclic peptide structures (Ulysse et al, 1995; Renner et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

A Photochromic Azobenzene Peptidomimetic of a β-Turn Model Peptide Structure as a Conformational Switch

et al. 2019

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The insertion of azobenzene moiety in complex molecular protein or peptide systems can lead to molecular switches to be used to determine kinetics of folding/unfolding properties of secondary structures, such as α-helix, β-turn, or β-hairpin. In fact, in azobenzene, absorption of light induces a reversible trans ↔ cis isomerization, which in turns generates a strain or a structure relaxation in the chain that causes peptide folding/unfolding. In particular azobenzene may permit reversible conformational control of hairpin formation. In the present work a synthetic photochromic azobenzene amino acid derivative was incorporated as a turn element to modify the synthetic peptide [Pro 7 ,Asn 8 ,Thr 10 ]CSF114 previously designed to fold as a type I β-turn structure in biomimetic HFA/water solution. In particular, the P-N-H fragment at positions 7–9, involved in a β-hairpin, was replaced by an azobenzene amino acid derivative (synthesized ad hoc ) to investigate if the electronic properties of the novel peptidomimetic analog could induce variations in the isomerization process. The absorption spectra of the azopeptidomimetic analog of the type I β-turn structure and of the azobenzene amino acid as control were measured as a function of the irradiation time exciting into the respective first ππ * and nπ * transition bands. Isomerization of the azopeptidomimetic results strongly favored by exciting into the ππ * transition. Moreover, conformational changes induced by the cis ↔ trans azopeptidomimetic switch were investigated by NMR in different solvents.

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“…1b), and thereby controlling the fold of the peptide. 78,[94][95][96][97][98][99][100] The applicability of azo-switches increased tremendously with works by Woolley and coworkers, who introduced a very versatile concept, post-translationally cross-linking two sites of a protein by a photoswitch (bifunctional control, see Figs. 1d,e).…”

Section: Strategies Of Azobenzene Photocontrolmentioning

confidence: 99%

“…1b. 99,100 Photoswitching initiated a conformational transformation of the system between a β-hairpin and an unfolded hydrophobic cluster. Unfolding takes a few nanoseconds only, while the reverse folding of this system requires more sampling of the conformational space and occurs on a 30 µs timescale.…”

Section: Time-resolved Studies On Small Peptides: Simple Model Systemsmentioning

confidence: 99%

Using azobenzene photocontrol to set proteins in motion

Božović

Janković²,

Hamm³

2021

Nat Rev Chem

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Controlling the activity of proteins with azobenzene photoswitches is a potent tool for manipulating their biological function. With the help of light, one can change e.g. binding affinities, control allostery or temper with complex biological processes. Additionally, due to their intrinsically fast photoisomerisation, azobenzene photoswitches can serve as triggers to initiate out-of-equilibrium processes. Such switching of the activity, therefore, initiates a cascade of conformational events, which can only be accessed with time-resolved methods. In this Review, we will show how combining the potency of azobenzene photoswitching with transient spectroscopic techniques helps to disclose the order of events and provide an experimental observation of biomolecular interactions in real-time. This will ultimately help us to understand how proteins accommodate, adapt and readjust their structure to answer an incoming signal and it will complete our knowledge of the dynamical character of proteins.

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Time-resolved infrared studies of the unfolding of a light triggered β-hairpin peptide

Cited by 13 publications

References 39 publications

Folding and Unfolding of the Short Light-Triggered β-Hairpin Peptide AzoChignolin Occurs within 100 ns

Folding and Unfolding of the Short Light-Triggered β-Hairpin Peptide AzoChignolin Occurs within 100 ns

A Photochromic Azobenzene Peptidomimetic of a β-Turn Model Peptide Structure as a Conformational Switch

Using azobenzene photocontrol to set proteins in motion

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