Hemithioindigo-based photoswitches as ultrafast light trigger in chromopeptides

Cordes, Thorben; Weinrich, Dirk; Kempa, S.; Riesselmann, K.; Herre, S.; Hoppmann, Christian; Rück‐Braun, K.; Zinth, Wolfgang

doi:10.1016/j.cplett.2006.07.043

Cited by 73 publications

(100 citation statements)

References 19 publications

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“…The isomerization quantum yield for the formation of the E-isomer in methanol at room temperature F PC is 11 % (illumination at 414 nm). [7] The stationary IR spectrum of HTI and the absorption difference in the IR induced by isomerization are shown in Figure 1 b. The absorption spectrum of the Z-form (solid curve, Figure 1 b, upper part) is stronger than that of the E-form (PSS400, broken curve).…”

Section: Stationary Characterization: Absorption and Emissionmentioning

confidence: 97%

“…[5][6][7][8] In addition, peptides containing light-triggered groups have been used to study the fastest processes in peptide folding. [5][6][7]9] Another important potential application of photochromic compounds is photomediated in vivo on/off switching of the activity of therapeutic compounds. [10,11] Different types of basic structures are used as photochromic centres, for example, stilbene and azobenzene.…”

Section: Introductionmentioning

confidence: 99%

“…[20] In a recent paper we investigated a special type of HTI molecule. [7] We demonstrated that the HTI structure is well suited for biological applications since it can be built into cyclic or linear peptide structures without losing its photochromic capabilities. The investigated HTI w-amino chromopeptides show ultrafast isomerization reactions in the 30-60 ps time range.…”

mentioning

confidence: 99%

“…The rate of isomerization was determined by time-resolved absorption (TA) measurements. [7] A more detailed description of the excited-state dynamics of HTI requires additional experimental information. These data would lead to an improved understanding of the underlying reaction mechanisms and would facilitate the design of photochromic compounds optimized for a specific switching problem.…”

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confidence: 99%

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Photochemical Z→E Isomerization of a Hemithioindigo/Hemistilbene ω‐Amino Acid

et al. 2007

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The molecule HTI, which combines hemithioindigo and hemistilbene molecular parts, allows reversible switching between two isomeric states. Photochromic behaviour of the HTI molecule is observed by irradiation with UV/Vis light. The photochemical reaction, a Z/E isomerization around the central double bond connecting the two molecular parts, is investigated by transient absorption and emission spectroscopy. For a special HTI molecule, namely, an omega-amino acid, the Z-->E isomerization process occurs on a timescale of 30 ps. In the course of the reaction fast processes on the 1-10 ps timescale are observed which point to motions of the molecule on the potential-energy surface of the excited state. The combination of transient absorption experiments in the visible spectral range with time-resolved fluorescence and infrared measurements reveal a photochemical pathway with three intermediate states. Together with a theoretical modelling procedure the experiments point to a sequential reaction scheme and give indications of the nature of the involved intermediates.

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Section: Stationary Characterization: Absorption and Emissionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

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Photochemical Z→E Isomerization of a Hemithioindigo/Hemistilbene ω‐Amino Acid

et al. 2007

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“…• Photoswitches embedded into the peptide backbone: In a similar approach, photoswitches such as azobenzene [95][96][97][98] or hemithioindigobased compounds [99] can be incorporated directly into the backbone of a peptide. The IR response of the amide I band of a small cyclic peptide has been investigated in great detail in our lab, showing that the peptide backbone can be stretched on an ultrafast 20 ps timescale upon cis-trans isomerization of an azo-moiety [bre03].…”

Section: Vibrational Spectroscopy Of Non-equilibrium Dynamics Of Peptmentioning

confidence: 99%

Ultrafast Peptide and Protein Dynamics by Vibrational Spectroscopy

Hamm

2008

Biological and Medical Physics, Biomedical Engineering

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Ultrafast peptide and protein dynamics by vibrational spectroscopyHamm, P Hamm, P (2008). Ultrafast peptide and protein dynamics by vibrational spectroscopy. In: Braun, M; Gilch, P; Zinth, W. Ultrashort laser pulses in biology and medicine. Proteins are molecular machines with a well-defined 3D structure, and it is mainly the success of X-ray and NMR spectroscopic techniques that made the tremendous progress in structural biology happen. However, it is also clear that biomolecular processes generally involve conformational changes of proteins and enzymes. Mostly due to a lack of appropriate spectroscopic tools, much less is known about the dynamics of protein structures. Protein dynamics occurs on a large range of time scales, which can coarsely be related to various length scales: Dynamics of tertiary and quaternary structure extends from milliseconds to seconds and even longer, while formation of secondary structure has been observed between 50 ns and a few microseconds [1][2][3][4][5][6][7][8][9][10][11][12]. Nevertheless, several experiments have provided strong hints for the relevance of even faster processes from the observation of large instantaneous signals, which could not be time-resolved [2,7,13]. For example, Thompson et al.[5] estimated a "zipping time" for a 21-residue α-helix of 300 ps (i.e., the time for closing of subsequent hydrogen bonds, once an initial helix turn is formed), while Huang et al. [7] indirectly concluded that helix nucleation might occur on a subnanosecond time scale. Also molecular dynamics (MD) simulations suggest that peptides and proteins can undergo considerable structural changes within 1 ns or less [8-10, 14, 15]. Hummer et al. [16] found the formation of the first α-helical turn within 0.1-1 ns in work on helix nucleation in short Ala and Gly based peptides. Daura et al. [9,17] simulated equilibrium folding/unfolding of a β-heptapeptide at the melting point and above to obtain statistics on the populations of the folded and unfolded states. Several folding/unfolding events were observed in a 50 ns trajectory, where the actual transitions from unfolded to folded conformations could be as fast as 50-100ps.

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Lichtgesteuerte Proteinbindung einer biologisch relevanten β‐Faltblattstruktur

et al. 2009

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[2] Außer C-terminale Proteinabschnitte können PDZ-Domänen auch interne Peptidmotive erkennen, die in dieselbe Bindungstasche binden wie C-terminale Motive. Das beste Beispiel für eine solche interne Liganderkennung wird für die erweiterte PDZDomäne der neuronalen Stickstoffmonoxid-Synthase (nNOS) gefunden, die an die PDZ-Domäne von a-1-Syntrophin oder die zweite PDZ-Domäne von PSD95 bindet.[3] Die Bildung des Heterodimers aus zwei unterschiedlichen PDZDomänen erfolgt über die b-Fingerstruktur von nNOS (30 Aminosäurereste), die an die PDZ-Domäne von Syntrophin bindet und dadurch die Membranassoziation von nNOS in der Skelettmuskulatur und die Induktion der Produktion von Stickstoffmonoxid als sekundären Botenstoff für die Muskelkontraktion bewirkt. [4] Für diese Bindung ist das interne Erkennungsmotiv -LETTF-der erweiterten PDZ-Domäne von nNOS wichtig, das im ersten Strang des Haarnadelmotivs lokalisiert ist (Schema 1) und eine stabile Konformation aus zwei antiparallelen Strängen bildet, die über eine Schleife verbunden sind.[5] Mimetika des nNOS-b-Fingers (Schema 2 a; Peptid 1) wurden in früheren Untersuchungen auf der Basis cyclischer Peptide entwickelt. Strukturrechnungen ergaben für Peptid 1 eine gute Übereinstimmung mit der Struktur des originalen bFingers. Bindungsuntersuchungen bestätigten eine Bindung an derselben Stelle des Proteins.[6] Ausgehend von diesen Ergebnissen wurde eine photoschaltbare w-Aminosäure in das cyclische Fingerpeptid 1 an Stelle des d-Pro-Gly-Schleifenelementes und der beide Seiten flankierenden Aminosäurereste eingebaut (Schema 2 b). Photoschaltbare w-Aminosäuren auf der Basis von Azobenzol [7] oder Hemithioindigo [8] sind geeignete Kandidaten zur Modulation von Peptidkonformationen, [9] da ihre Photoisomerisierung äußerst schnell verläuft, [10] was ein Verfolgen der Konformationsübergänge im Bereich von Pico-bis zu Femtosekunden ermöglicht.[11] Für biologische Anwendungen [12] hat sich Azobenzol als sehr effektiv erwiesen, weil es eine cisÐtrans-Isomerisierung um die zentrale N=N-Bindung mit hohen Isomerisierungsausbeuten und beträchtlichen Strukturänderun-

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Hemithioindigo-based photoswitches as ultrafast light trigger in chromopeptides

Cited by 73 publications

References 19 publications

Photochemical Z→E Isomerization of a Hemithioindigo/Hemistilbene ω‐Amino Acid

Photochemical Z→E Isomerization of a Hemithioindigo/Hemistilbene ω‐Amino Acid

Ultrafast Peptide and Protein Dynamics by Vibrational Spectroscopy

Lichtgesteuerte Proteinbindung einer biologisch relevanten β‐Faltblattstruktur

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