“…2‐aza Tryptophan ( W22 ) has conflicting reports about its suitability as a translation substrate [152–154] . Chou and co‐workers have recently investigated the 2,6‐ and 2,7 di‐aza substrates ( W23 and W24 ), as fluorescent probes of hydration [155–158] . The benzene ring in the imidazole can be substituted with a 5 member‐ring containing a sulfur or selenium atom ( W25 – W28 ) [141] .…”
Section: E Coli Aminoacyl‐trna Synthetases and Their Substratesmentioning
In this comprehensive review, I focus on the twenty E. coli aminoacyl‐tRNA synthetases and their ability to charge non‐canonical amino acids (ncAAs) onto tRNAs. The promiscuity of these enzymes has been harnessed for diverse applications including understanding and engineering of protein function, creation of organisms with an expanded genetic code, and the synthesis of diverse peptide libraries for drug discovery. The review catalogues the structures of all known ncAA substrates for each of the 20 E. coli aminoacyl‐tRNA synthetases, including ncAA substrates for engineered versions of these enzymes. Drawing from the structures in the list, I highlight trends and novel opportunities for further exploitation of these ncAAs in the engineering of protein function, synthetic biology, and in drug discovery.
“…2‐aza Tryptophan ( W22 ) has conflicting reports about its suitability as a translation substrate [152–154] . Chou and co‐workers have recently investigated the 2,6‐ and 2,7 di‐aza substrates ( W23 and W24 ), as fluorescent probes of hydration [155–158] . The benzene ring in the imidazole can be substituted with a 5 member‐ring containing a sulfur or selenium atom ( W25 – W28 ) [141] .…”
Section: E Coli Aminoacyl‐trna Synthetases and Their Substratesmentioning
In this comprehensive review, I focus on the twenty E. coli aminoacyl‐tRNA synthetases and their ability to charge non‐canonical amino acids (ncAAs) onto tRNAs. The promiscuity of these enzymes has been harnessed for diverse applications including understanding and engineering of protein function, creation of organisms with an expanded genetic code, and the synthesis of diverse peptide libraries for drug discovery. The review catalogues the structures of all known ncAA substrates for each of the 20 E. coli aminoacyl‐tRNA synthetases, including ncAA substrates for engineered versions of these enzymes. Drawing from the structures in the list, I highlight trends and novel opportunities for further exploitation of these ncAAs in the engineering of protein function, synthetic biology, and in drug discovery.
“…They found that this compound provided dual emission peaks at 335 and 495 nm in neutral water, indicating the occurrence of an ESInterPT process through an intermolecular H-bond wire of water. Thus, 2,7-DAI could be potentially used as an optical probe for the surrounding water environment of proteins. ,− Its photophysical properties in aqueous environment from experiment were confirmed by theoretical calculations using microsolvation on top with an implicit solvent model. , The dual emission peaks were suggested from N* around 305–338 nm and T* around 419–469 nm. , For ESInterPT, the multiple PT processes of 2,7-DAI(H 2 O) n (where n = 1–2) using microsolvation on top with an implicit solvent model considering only the one hydration shell have been theoretically reported. , The multiple PT reactions of 2,7-DAI(H 2 O) 1 and 2,7-DAI(H 2 O) 2 occurred with rather high PT barriers (>6 kcal/mol) in the S 1 state through intermolecular H-bonds of water wire. However, the experiment confirmed the occurrence of ESInterPT in 2,7-DAI in a water environment; hence, using only one hydration shell to describe the PT behavior might not be enough for description of the ESInterPT process in bulk water.…”
Section: Introductionmentioning
confidence: 89%
“…Through the static calculations, potential energy surfaces along the PT processes and the reaction energies of all 2,7-DAI(H 2 O) n complexes (two hydration shells) are calculated to give the energy required of ESInterPT in terms of the PT barrier and reaction energy. Moreover, the potential energy surfaces and reaction energies of 2,7-DAI complexes having only one hydration shell [2,7-DAI(H 2 O) 1 , 2,7-DAI(H 2 O) 2 , and 2,7-DAI(H 2 O) 3 ] − ,, were also computed and further employed to investigate the role of the second hydration shell. To understand the role of the second hydration shell, the strength of the intermolecular H-bond for all 2,7-DAI complexes with water molecules consisting of either one or two hydration shells is analyzed using important parameters from optimized structures, spectral changes of simulated infrared spectra involved in the PT process, and topology analysis.…”
The detailed excited-state intermolecular proton transfer (ESInterPT) mechanism of 2,7-diazaindole with water wires consisting of either one or two shells [2,7-DAI(H 2 O) n ; n = 1−5] has been theoretically explored by time-dependent density functional theory using microsolvation with an implicit solvent model. On the basis of the excited-state potential energy surfaces along the proton transfer (PT) coordinates, among all 2,7-DAI(H 2 O) n , the multiple ESInterPT of 2,7-DAI(H 2 O) 2+3 through the first hydration shell (inner circuit) is the most easy process to occur with the lowest PT barrier and a highly exothermic reaction. The lowest PT barrier resulted from the outer three waters pushing the inner circuit waters to be much closer to 2,7-DAI, leading to the enhanced intermolecular hydrogen-bonding strength of the inner two waters. Moreover, on-thefly dynamic simulations show that the multiple ESInterPT mechanism of 2,7-DAI(H 2 O) 2+3 is the triple PT in a stepwise mechanism with the highest PT probability. This solvation effect using microsolvation and dynamic simulation is a cost-effect approach to reveal the solvent-assisted multiple proton relay of chromophores based on excited-state proton transfer.
“…Interestingly, the cell synthetic machinery is able to recognize these molecules as natural Trp-molecules and to insert them into desired protein sites. Combination of fluorescence responses of inserted 2,7-diaza-Trp-and 2,6-diaza-Trp-residues was suggested for studying the water-associated conformational mobility in the active sites in proteins [85] . Fig.…”
Section: Proton In Chemical and Biochemical Transformationsmentioning
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