Synthesis of ?-(1-azulenyl)-L-alanine as a potential blue-colored fluorescent tryptophan analog and its use in peptide synthesis

Loidl, Günther; Musiol, Hans-Jürgen; Budiša, Nediljko; Huber, Robert; Silvente-Poirot, Sandrine; Fourmy, Daniel; Moröder, Luis

doi:10.1002/(sici)1099-1387(200003)6:3<139::aid-psc240>3.0.co;2-6

Cited by 39 publications

(28 citation statements)

References 15 publications

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“…[17,18] They allow for the design of spectroscopic tools with properties that are different from those of natural moieties,t hereby permitting selective excitation and unique signal emission. [20,21] Second, upon excitation at 600 nm to its S 1 state,A zAla undergoes ultrafast internal S 1 !S 0 conversion, [2] thereby converting the photon energy into vibrational energy on the sub-picosecond timescale. Thedeep-blue tryptophan (Trp) analogue b-(1azulenyl)-l-alanine (AzAla;F igure 1a), exhibits two distinct functions,a mong which one can choose by using different excitation wavelengths because the azulene side chain is ar are exception of Kashasr ule: [19] First, upon excitation at 340 nm to its S 2 state,AzAla emits at 380 nm as afluorescent label, spectrally separated from the cAA Tr ps ignal, combining superior fluorescence and photophysical properties.…”

Section: Anisotropicvibrationalenergytransfer(vet)isexpectedtomentioning

confidence: 99%

Site‐Resolved Observation of Vibrational Energy Transfer Using a Genetically Encoded Ultrafast Heater

et al. 2019

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Allosteric information transfer in proteins has been linked to distinct vibrational energy transfer (VET) pathways in an umber of theoretical studies.E xperimental evidence for such pathways, however,i ss parse because site-selective injection of vibrational energy into aprotein, that is,localized heating,isrequired for their investigation. Here,wesolved this problem by the site-specific incorporation of the non-canonical amino acid b-(1-azulenyl)-l-alanine (AzAla) through genetic code expansion. As an exception to Kashasr ule,A zAla undergoes ultrafast internal conversion and heating after S 1 excitation while upon S 2 excitation, it serves as af luorescent label. We equipped PDZ3, ap rotein interaction domain of postsynaptic density protein 95, with this ultrafast heater at two distinct positions.W eindeed observed VET from the incorporation sites in the protein to ab ound peptide ligand on the picosecond timescale by ultrafast IR spectroscopy. This approach based on genetically encoded AzAla paves the way for detailed studies of VET and its role in aw ide range of proteins. Dr.J .Jaric Present address:H ospira Zagreb d.o.o.,aPfizer company Prudnicka cesta 60, 10291 Prigorje Brdovecko (Croatia) [ + + ]T hese authors contributed equally to this work. Supportinginformation and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

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Section: Anisotropicvibrationalenergytransfer(vet)isexpectedtomentioning

confidence: 99%

Site‐Resolved Observation of Vibrational Energy Transfer Using a Genetically Encoded Ultrafast Heater

et al. 2019

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“…This was demonstrated by the synthesis of such analogues in which the imino group was replaced with other heteroatoms (selenium, sulfur, or oxygen); the resulting amino acids were translationally inactive 77. For example, Trp‐like blue amino acid 35 with an azulene ring system is not a substrate for native translation machinery108 even when it is chemically charged onto tRNA for an in vitro reaction.…”

Section: Power and Limits Of Selective Pressure: Engineering A “Sementioning

confidence: 99%

Prolegomena to Future Experimental Efforts on Genetic Code Engineering by Expanding Its Amino Acid Repertoire

2004

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Protein synthesis and its relation to the genetic code was for a long time a central issue in biology. Rapid experimental progress throughout the past decade, crowned with the recently elucidated ribosomal structures, provided an almost complete description of this process. In addition important experiments provided solid evidence that the natural protein translation machinery can be reprogrammed to encode genetically a vast number of non-coded (i.e. noncanonical) amino acids. Indeed, in the set of 20 canonical amino acids as prescribed by the universal genetic code, many desirable functionalities, such as halogeno, keto, cyano, azido, nitroso, nitro, and silyl groups, as well as C=C or C[triple bond]C bonds, are absent. The ability to encode genetically such chemical diversity will enable us to reprogram living cells, such as bacteria, to express tailor-made proteins exhibiting functional diversity. Accordingly, genetic code engineering has developed into an exciting emerging research field at the interface of biology, chemistry, and physics.

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“…The blue‐colored azulenyl α‐amino acid has been synthesized with good yield and purity only recently 20. The peculiar spectroscopic feature of azulene is the anomalous high‐yield fluorescence from the S 2 state, while the S 1 state rapidly relaxes to the ground state via ultrafast (<2 ps) internal conversion, showing only a very weak fluorescence (Θ f ≈10 −6 ) 21–23.…”

Section: Introductionmentioning

confidence: 99%

Structural properties and photophysical behavior of conformationally constrained hexapeptides functionalized with a new fluorescent analog of tryptophan and a nitroxide radical quencher

et al. 2004

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The influence of the conformational properties on the photophysics of two de novo designed hexapeptides was studied by spectroscopic measurements (ir, NMR, steady-state, and time resolved fluorescence) and molecular mechanics calculations. The peptide sequences comprise two nonproteinogenic residues: a beta-(1-azulenyl)-L-alanine (Aal) residue, obtained by formally functionalizing the Ala side chain with the azulene chromophore, and a Calpha-tetrasubstituted alpha-amino acid (TOAC), incorporating a nitroxide group in a cycloalkyl moiety. Aal represents a new fluorescent, quasi-isosteric Trp analog and TOAC a stable radical species, frequently used as a paramagnetic probe in biochemical studies. The peptide chains differ in the sequence position of the two probes and are heavily based on Aib (alpha-aminoisobutyric acid) residues to generate conformationally restricted helical structures, as confirmed by both spectroscopic and computational results. The conformationally controlled, excited state interactions, determining the photophysical relaxation of the Aal*/TOAC pair, are also discussed.

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Synthesis of ?-(1-azulenyl)-L-alanine as a potential blue-colored fluorescent tryptophan analog and its use in peptide synthesis

Cited by 39 publications

References 15 publications

Site‐Resolved Observation of Vibrational Energy Transfer Using a Genetically Encoded Ultrafast Heater

Site‐Resolved Observation of Vibrational Energy Transfer Using a Genetically Encoded Ultrafast Heater

Prolegomena to Future Experimental Efforts on Genetic Code Engineering by Expanding Its Amino Acid Repertoire

Structural properties and photophysical behavior of conformationally constrained hexapeptides functionalized with a new fluorescent analog of tryptophan and a nitroxide radical quencher

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