1
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Jann C, Giofré S, Bhattacharjee R, Lemke EA. Cracking the Code: Reprogramming the Genetic Script in Prokaryotes and Eukaryotes to Harness the Power of Noncanonical Amino Acids. Chem Rev 2024. [PMID: 39120726 DOI: 10.1021/acs.chemrev.3c00878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/10/2024]
Abstract
Over 500 natural and synthetic amino acids have been genetically encoded in the last two decades. Incorporating these noncanonical amino acids into proteins enables many powerful applications, ranging from basic research to biotechnology, materials science, and medicine. However, major challenges remain to unleash the full potential of genetic code expansion across disciplines. Here, we provide an overview of diverse genetic code expansion methodologies and systems and their final applications in prokaryotes and eukaryotes, represented by Escherichia coli and mammalian cells as the main workhorse model systems. We highlight the power of how new technologies can be first established in simple and then transferred to more complex systems. For example, whole-genome engineering provides an excellent platform in bacteria for enabling transcript-specific genetic code expansion without off-targets in the transcriptome. In contrast, the complexity of a eukaryotic cell poses challenges that require entirely new approaches, such as striving toward establishing novel base pairs or generating orthogonally translating organelles within living cells. We connect the milestones in expanding the genetic code of living cells for encoding novel chemical functionalities to the most recent scientific discoveries, from optimizing the physicochemical properties of noncanonical amino acids to the technological advancements for their in vivo incorporation. This journey offers a glimpse into the promising developments in the years to come.
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Affiliation(s)
- Cosimo Jann
- Biocenter, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- IMB Postdoc Programme (IPPro), 55128 Mainz, Germany
| | - Sabrina Giofré
- Biocenter, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- IMB Postdoc Programme (IPPro), 55128 Mainz, Germany
| | - Rajanya Bhattacharjee
- Biocenter, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- IMB International PhD Programme (IPP), 55128 Mainz, Germany
| | - Edward A Lemke
- Biocenter, Johannes Gutenberg University Mainz, 55128 Mainz, Germany
- Institute of Molecular Biology (IMB), 55128 Mainz, Germany
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2
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Blain-Hartung M, Johannes von Sass G, Plaickner J, Katz S, Tu Hoang O, Andrea Mroginski M, Esser N, Budisa N, Forest KT, Hildebrandt P. On the Role of a Conserved Tryptophan in the Chromophore Pocket of Cyanobacteriochrome. J Mol Biol 2024; 436:168227. [PMID: 37544357 DOI: 10.1016/j.jmb.2023.168227] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/26/2023] [Accepted: 07/31/2023] [Indexed: 08/08/2023]
Abstract
The cyanobacteriochrome Slr1393 can be photoconverted between a red (Pr) and green absorbing form (Pg). The recently determined crystal structures of both states suggest a major movement of Trp496 from a stacking interaction with ring D of the phycocyanobilin (PCB) chromophore in Pr to a position outside the chromophore pocket in Pg. Here, we investigated the role of this amino acid during photoconversion in solution using engineered protein variants in which Trp496 was substituted by natural and non-natural amino acids. These variants and the native protein were studied by various spectroscopic techniques (UV-vis absorption, fluorescence, IR, NIR and UV resonance Raman) complemented by theoretical approaches. Trp496 is shown to affect the electronic transition of PCB and to be essential for the thermal equilibrium between Pr and an intermediate state O600. However, Trp496 is not required to stabilize the tilted orientation of ring D in Pr, and does not play a role in the secondary structure changes of Slr1393 during the Pr/Pg transition. The present results confirm the re-orientation of Trp496 upon Pr → Pg conversion, but do not provide evidence of a major change in the microenvironment of this residue. Structural models indicate the penetration of water molecules into the chromophore pocket in both Pr and Pg states and thus water-Trp contacts, which can readily account for the subtle spectral changes between Pr and Pg. Thus, we conclude that reorientation of Trp496 during the Pr-to-Pg photoconversion in solution is not associated with a major change in the dielectric environment in the two states.
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Affiliation(s)
- Matthew Blain-Hartung
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Georg Johannes von Sass
- Technische Universität Berlin, Institut für Chemie, Sekr. CL1, Müller-Breslau-Str.10, D-10623 Berlin, Germany
| | - Julian Plaickner
- Technische Universität Berlin, Institut für Festkörperphysik, Sekr. EW 6-1, Hardenbergstraße 36, 10623 Berlin, Germany
| | - Sagie Katz
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Oanh Tu Hoang
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Maria Andrea Mroginski
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, D-10623 Berlin, Germany
| | - Norbert Esser
- Technische Universität Berlin, Institut für Festkörperphysik, Sekr. EW 6-1, Hardenbergstraße 36, 10623 Berlin, Germany; Leibniz-Institut für Analytische Wissenschaften-ISAS-e.V, Schwarzschildstraße 8, 12489 Berlin, Germany
| | - Nediljko Budisa
- Technische Universität Berlin, Institut für Chemie, Sekr. CL1, Müller-Breslau-Str.10, D-10623 Berlin, Germany; Department of Chemistry, University of Manitoba, 144 Dysart Rd, 360 Parker Building, R3T 2N2 Winnipeg, Manitoba, Canada
| | - Katrina T Forest
- University of Wisconsin-Madison, Department of Bacteriology, 1550 Linden Dr., Madison, WI 53706, USA
| | - Peter Hildebrandt
- Technische Universität Berlin, Institut für Chemie, Sekr. PC 14, Straße des 17. Juni 135, D-10623 Berlin, Germany.
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3
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Romei M, von Krusenstiern EV, Ridings ST, King RN, Fortier JC, McKeon CA, Nichols KM, Charkoudian LK, Londergan CH. Frequency Changes in Terminal Alkynes Provide Strong, Sensitive, and Solvatochromic Raman Probes of Biochemical Environments. J Phys Chem B 2023; 127:85-94. [PMID: 36538691 PMCID: PMC9841980 DOI: 10.1021/acs.jpcb.2c06176] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 11/19/2022] [Indexed: 12/24/2022]
Abstract
The C≡C stretching frequencies of terminal alkynes appear in the "clear" window of vibrational spectra, so they are attractive and increasingly popular as site-specific probes in complicated biological systems like proteins, cells, and tissues. In this work, we collected infrared (IR) absorption and Raman scattering spectra of model compounds, artificial amino acids, and model proteins that contain terminal alkyne groups, and we used our results to draw conclusions about the signal strength and sensitivity to the local environment of both aliphatic and aromatic terminal alkyne C≡C stretching bands. While the IR bands of alkynyl model compounds displayed surprisingly broad solvatochromism, their absorptions were weak enough that alkynes can be ruled out as effective IR probes. The same solvatochromism was observed in model compounds' Raman spectra, and comparisons to published empirical solvent scales (including a linear regression against four meta-aggregated solvent parameters) suggested that the alkyne C≡C stretching frequency mainly reports on local electronic interactions (i.e., short-range electron donor-acceptor interactions) with solvent molecules and neighboring functional groups. The strong solvatochromism observed here for alkyne stretching bands introduces an important consideration for Raman imaging studies based on these signals. Raman signals for alkynes (especially those that are π-conjugated) can be exceptionally strong and should permit alkynyl Raman signals to function as probes at very low concentrations, as compared to other widely used vibrational probe groups like azides and nitriles. We incorporated homopropargyl glycine into a transmembrane helical peptide via peptide synthesis, and we installed p-ethynylphenylalanine into the interior of the Escherichia coli fatty acid acyl carrier protein using a genetic code expansion technique. The Raman spectra from each of these test systems indicate that alkynyl C≡C bands can act as effective and unique probes of their local biomolecular environments. We provide guidance for the best possible future uses of alkynes as solvatochromic Raman probes, and while empirical explanations of the alkyne solvatochromism are offered, open questions about its physical basis are enunciated.
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Affiliation(s)
- Matthew
G. Romei
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Eliana V. von Krusenstiern
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Stephen T. Ridings
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Renee N. King
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Julia C. Fortier
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Caroline A. McKeon
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Krysta M. Nichols
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Louise K. Charkoudian
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
| | - Casey H. Londergan
- Department of Chemistry, Haverford College, 370 Lancaster Avenue, Haverford, Pennsylvania 19041-1392, United States
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4
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Lee B, Papoutsis BM, Wong NY, Piacentini J, Kearney C, Huggins NA, Cruz N, Ng TT, Hao KH, Kramer JS, Fenlon EE, Nerenberg PS, Phillips-Piro CM, Brewer SH. Unraveling Complex Local Protein Environments with 4-Cyano-l-phenylalanine. J Phys Chem B 2022; 126:8957-8969. [PMID: 36317866 PMCID: PMC10234312 DOI: 10.1021/acs.jpcb.2c05954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
We present a multifaceted approach to effectively probe complex local protein environments utilizing the vibrational reporter unnatural amino acid (UAA) 4-cyano-l-phenylalanine (pCNPhe) in the model system superfolder green fluorescent protein (sfGFP). This approach combines temperature-dependent infrared (IR) spectroscopy, X-ray crystallography, and molecular dynamics (MD) simulations to provide a molecular interpretation of the local environment of the nitrile group in the protein. Specifically, a two-step enantioselective synthesis was developed that provided an 87% overall yield of pCNPhe in high purity without the need for chromatography. It was then genetically incorporated individually at three unique sites (74, 133, and 149) in sfGFP to probe these local protein environments. The incorporation of the UAA site-specifically in sfGFP utilized an engineered, orthogonal tRNA synthetase in E. coli using the Amber codon suppression protocol, and the resulting UAA-containing sfGFP constructs were then explored with this approach. This methodology was effectively utilized to further probe the local environments of two surface sites (sites 133 and 149) that we previously explored with room temperature IR spectroscopy and X-ray crystallography and a new interior site (site 74) featuring a complex local environment around the nitrile group of pCNPhe. Site 133 was found to be solvent-exposed, while site 149 was partially buried. Site 74 was found to consist of three distinct local environments around the nitrile group including nonspecific van der Waals interactions, hydrogen-bonding to a structural water, and hydrogen-bonding to a histidine side chain.
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Affiliation(s)
- ByungUk Lee
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Brianna M. Papoutsis
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Nathan Y. Wong
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Juliana Piacentini
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Caroline Kearney
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Nia A. Huggins
- Department of Biological Sciences, California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032
| | - Nicole Cruz
- Department of Biological Sciences, California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032
| | - Tracey T. Ng
- Department of Physics and Astronomy, California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032
| | - Kexin Heather Hao
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Jeremy S. Kramer
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Edward E. Fenlon
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Paul S. Nerenberg
- Department of Biological Sciences, California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032
- Department of Physics and Astronomy, California State University, Los Angeles, 5151 State University Drive, Los Angeles, CA 90032
| | | | - Scott H. Brewer
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
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5
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Adams ZC, Olson EJ, Lopez-Silva TL, Lian Z, Kim AY, Holcomb M, Zimmermann J, Adhikary R, Dawson PE. Direct observation of peptide hydrogel self-assembly. Chem Sci 2022; 13:10020-10028. [PMID: 36128231 PMCID: PMC9430618 DOI: 10.1039/d1sc06562a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 07/14/2022] [Indexed: 11/30/2022] Open
Abstract
The characterization of self-assembling molecules presents significant experimental challenges, especially when associated with phase separation or precipitation. Transparent window infrared (IR) spectroscopy leverages site-specific probes that absorb in the “transparent window” region of the biomolecular IR spectrum. Carbon–deuterium (C–D) bonds are especially compelling transparent window probes since they are non-perturbative, can be readily introduced site selectively into peptides and proteins, and their stretch frequencies are sensitive to changes in the local molecular environment. Importantly, IR spectroscopy can be applied to a wide range of molecular samples regardless of solubility or physical state, making it an ideal technique for addressing the solubility challenges presented by self-assembling molecules. Here, we present the first continuous observation of transparent window probes following stopped-flow initiation. To demonstrate utility in a self-assembling system, we selected the MAX1 peptide hydrogel, a biocompatible material that has significant promise for use in drug delivery and medical applications. C–D labeled valine was synthetically introduced into five distinct positions of the twenty-residue MAX1 β-hairpin peptide. Consistent with current structural models, steady-state IR absorption frequencies and linewidths of C–D bonds at all labeled positions indicate that these side chains occupy a hydrophobic region of the hydrogel and that the motion of side chains located in the middle of the hairpin is more restricted than those located on the hairpin ends. Following a rapid change in ionic strength to initiate self-assembly, the peptide absorption spectra were monitored as function of time, allowing determination of site-specific time constants. We find that within the experimental resolution, MAX1 self-assembly occurs as a cooperative process. These studies suggest that stopped-flow transparent window FTIR can be extended to other time-resolved applications, such as protein folding and enzyme kinetics. To facilitate the characterization of phase-transitioning molecules, site-specific non-perturbative infrared probes are leveraged for continuous observation of the self-assembly of fibrils in a peptide hydrogel following stopped-flow initiation.![]()
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Affiliation(s)
- Zoë C. Adams
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Erika J. Olson
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Tania L. Lopez-Silva
- Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health, Frederick, MD 21702, USA
| | - Zhengwen Lian
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Audrey Y. Kim
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Matthew Holcomb
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Jörg Zimmermann
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Ramkrishna Adhikary
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
| | - Philip E. Dawson
- Department of Chemistry, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California, 92037, USA
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6
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Zhang H, Zhang H, Chen C. Investigating the folding mechanism of the N-terminal domain of ribosomal protein L9. Proteins 2021; 89:832-844. [PMID: 33576138 DOI: 10.1002/prot.26062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 01/04/2021] [Accepted: 01/31/2021] [Indexed: 11/10/2022]
Abstract
Protein folding is a popular topic in the life science. However, due to the limited sampling ability of experiments and simulations, the general folding mechanism is not yet clear to us. In this work, we study the folding of the N-terminal domain of ribosomal protein L9 (NTL9) in detail by a mixing replica exchange molecular dynamics method. The simulation results are close to previous experimental observations. According to the Markov state model, the folding of the protein follows a nucleation-condensation path. Moreover, after the comparison to its 39-residue β-α-β motif, we find that the helix at the C-terminal has a great influence on the folding process of the intact protein, including the nucleation of the key residues in the transition state ensemble and the packing of the hydrophobic residues in the native state.
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Affiliation(s)
- Haozhe Zhang
- Biomolecular Physics and Modeling Group, School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Haomiao Zhang
- Biomolecular Physics and Modeling Group, School of Physics, Huazhong University of Science and Technology, Wuhan, China
| | - Changjun Chen
- Biomolecular Physics and Modeling Group, School of Physics, Huazhong University of Science and Technology, Wuhan, China
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7
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Luo M, Eaton CN, Hess KR, Phillips-Piro CM, Brewer SH, Fenlon EE. Paired Spectroscopic and Crystallographic Studies of Proteases. ChemistrySelect 2019; 4:9836-9843. [PMID: 34169145 PMCID: PMC8221577 DOI: 10.1002/slct.201902049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/23/2019] [Indexed: 12/13/2022]
Abstract
The active sites of subtilisin and trypsin have been studied by paired IR spectroscopic and X-ray crystallographic studies. The active site serines of the proteases were reacted with 4-cyanobenzenesulfonyl fluoride (CBSF), an inhibitor that contains a nitrile vibrational reporter. The nitrile stretch vibration of the water-soluble inhibitor model, potassium 4-cyanobenzenesulfonate (KCBSO), and the inhibitor were calibrated by IR solvent studies in H2O/DMSO and the frequency-temperature line-slope (FTLS) method in H2O and THF. The inhibitor complexes were examined by FTLS and the slopes of the best fit lines for subtilisin-CBS and trypsin-CBS in aqueous buffer were both measured to be -3.5×10-2 cm-1/°C. These slopes were intermediate in value between that of KCBSO in aqueous buffer and CBSF in THF, which suggests that the active-site nitriles in both proteases are mostly solvated. The X-ray crystal structures of the subtilisin-CBS and trypsin-CBS complexes were solved at 1.27 and 1.32 Å, respectively. The inhibitor was modelled in two conformations in subtilisin-CBS and in one conformation in the trypsin-CBS. The crystallographic data support the FTLS data that the active-site nitrile groups are mostly solvated and participate in hydrogen bonds with water molecules. The combination of IR spectroscopy utilizing vibrational reporters paired with X-ray crystallography provides a powerful approach to studying protein structure.
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Affiliation(s)
- Meiqi Luo
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Christopher N. Eaton
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Kenneth R. Hess
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | | | - Scott H. Brewer
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
| | - Edward E. Fenlon
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003
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8
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Zhang H, Gong Q, Zhang H, Chen C. Combining the biased and unbiased sampling strategy into one convenient free energy calculation method. J Comput Chem 2019; 40:1806-1815. [PMID: 30942500 DOI: 10.1002/jcc.25834] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 03/15/2019] [Accepted: 03/17/2019] [Indexed: 12/14/2022]
Abstract
Constructing a free energy landscape for a large molecule is difficult. One has to use either a high temperature or a strong driving force to enhance the sampling on the free energy barriers. In this work, we propose a mixed method that combines these two kinds of acceleration strategies into one simulation. First, it applies an adaptive biasing potential to some replicas of the molecule. These replicas are particularly accelerated in a collective variable space. Second, it places some unbiased and exchangeable replicas at various temperature levels. These replicas generate unbiased sampling data in the canonical ensemble. To improve the sampling efficiency, biased replicas transfer their state variables to the unbiased replicas after equilibrium by Monte Carlo trial moves. In comparison to previous integrated methods, it is more convenient for users. It does not need an initial reference biasing potential to guide the sampling of the molecule. And it is also unnecessary to insert many replicas for the requirement of passing the free energy barriers. The free energy calculation is accomplished in a single stage. It samples the data as fast as a biased simulation and it processes the data as simple as an unbiased simulation. The method provides a minimalist approach to the construction of the free energy landscape. © 2019 Wiley Periodicals, Inc.
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Affiliation(s)
- Haomiao Zhang
- Biomolecular Physics and Modeling Group, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
| | - Qiankun Gong
- Biomolecular Physics and Modeling Group, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
| | - Haozhe Zhang
- Biomolecular Physics and Modeling Group, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
| | - Changjun Chen
- Biomolecular Physics and Modeling Group, School of Physics, Huazhong University of Science and Technology, Wuhan 430074, Hubei, China
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9
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Ferrie JJ, Haney CM, Yoon J, Pan B, Lin YC, Fakhraai Z, Rhoades E, Nath A, Petersson EJ. Using a FRET Library with Multiple Probe Pairs To Drive Monte Carlo Simulations of α-Synuclein. Biophys J 2019; 114:53-64. [PMID: 29320696 DOI: 10.1016/j.bpj.2017.11.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Revised: 10/21/2017] [Accepted: 11/06/2017] [Indexed: 01/24/2023] Open
Abstract
We describe a strategy for experimentally-constraining computational simulations of intrinsically disordered proteins (IDPs), using α-synuclein, an IDP with a central role in Parkinson's disease pathology, as an example. Previously, data from single-molecule Förster Resonance Energy Transfer (FRET) experiments have been effectively utilized to generate experimentally constrained computational models of IDPs. However, the fluorophores required for single-molecule FRET experiments are not amenable to the study of short-range (<30 Å) interactions. Using ensemble FRET measurements allows one to acquire data from probes with multiple distance ranges, which can be used to constrain Monte Carlo simulations in PyRosetta. To appropriately employ ensemble FRET data as constraints, we optimized the shape and weight of constraining potentials to afford ensembles of structures that are consistent with experimental data. We also used this approach to examine the structure of α-synuclein in the presence of the compacting osmolyte trimethylamine-N-oxide. Despite significant compaction imparted by 2 M trimethylamine-N-oxide, the underlying ensemble of α-synuclein remains largely disordered and capable of aggregation, also in agreement with experimental data. These proof-of-concept experiments demonstrate that our modeling protocol enables one to efficiently generate experimentally constrained models of IDPs that incorporate atomic-scale detail, allowing one to study an IDP under a variety of conditions.
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Affiliation(s)
- John J Ferrie
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Conor M Haney
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jimin Yoon
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Buyan Pan
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Yi-Chih Lin
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Zahra Fakhraai
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Elizabeth Rhoades
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Abhinav Nath
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, Washington
| | - E James Petersson
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania.
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10
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Kossowska D, Park K, Park JY, Lim C, Kwak K, Cho M. Rational Design of an Acetylenic Infrared Probe with Enhanced Dipole Strength and Increased Vibrational Lifetime. J Phys Chem B 2019; 123:6274-6281. [DOI: 10.1021/acs.jpcb.9b04925] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Dorota Kossowska
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Kwanghee Park
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
| | - Jun Young Park
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Chaiho Lim
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Kyungwon Kwak
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Minhaeng Cho
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
- Department of Chemistry, Korea University, Seoul 02841, Korea
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11
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Vibrational Approach to the Dynamics and Structure of Protein Amyloids. Molecules 2019; 24:molecules24010186. [PMID: 30621325 PMCID: PMC6337179 DOI: 10.3390/molecules24010186] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 12/31/2018] [Accepted: 01/02/2019] [Indexed: 02/06/2023] Open
Abstract
Amyloid diseases, including neurodegenerative diseases such as Alzheimer’s and Parkinson’s, are linked to a poorly understood progression of protein misfolding and aggregation events that culminate in tissue-selective deposition and human pathology. Elucidation of the mechanistic details of protein aggregation and the structural features of the aggregates is critical for a comprehensive understanding of the mechanisms of protein oligomerization and fibrillization. Vibrational spectroscopies, such as Fourier transform infrared (FTIR) and Raman, are powerful tools that are sensitive to the secondary structure of proteins and have been widely used to investigate protein misfolding and aggregation. We address the application of the vibrational approaches in recent studies of conformational dynamics and structural characteristics of protein oligomers and amyloid fibrils. In particular, introduction of isotope labelled carbonyl into a peptide backbone, and incorporation of the extrinsic unnatural amino acids with vibrational moieties on the side chain, have greatly expanded the ability of vibrational spectroscopy to obtain site-specific structural and dynamic information. The applications of these methods in recent studies of protein aggregation are also reviewed.
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12
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Liu H, Morris C, Lantz R, Kent TW, Elbassal EA, Wojcikiewicz EP, Du D. Residue‐Specific Dynamics and Local Environmental Changes in Aβ40 Oligomer and Fibril Formation. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201802490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Haiyang Liu
- Department of Chemistry and BiochemistryFlorida Atlantic University 777 Glades Road Boca Raton FL 33431 USA
| | - Clifford Morris
- Department of Chemistry and BiochemistryFlorida Atlantic University 777 Glades Road Boca Raton FL 33431 USA
| | - Richard Lantz
- Department of Chemistry and BiochemistryFlorida Atlantic University 777 Glades Road Boca Raton FL 33431 USA
| | - Thomas W. Kent
- Department of Chemistry and BiochemistryFlorida Atlantic University 777 Glades Road Boca Raton FL 33431 USA
| | - Esmail A. Elbassal
- Department of Chemistry and BiochemistryFlorida Atlantic University 777 Glades Road Boca Raton FL 33431 USA
| | - Ewa P. Wojcikiewicz
- Department of Biomedical ScienceFlorida Atlantic University 777 Glades Road Boca Raton FL 33431 USA
| | - Deguo Du
- Department of Chemistry and BiochemistryFlorida Atlantic University 777 Glades Road Boca Raton FL 33431 USA
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13
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Liu H, Morris C, Lantz R, Kent TW, Elbassal EA, Wojcikiewicz EP, Du D. Residue-Specific Dynamics and Local Environmental Changes in Aβ40 Oligomer and Fibril Formation. Angew Chem Int Ed Engl 2018; 57:8017-8021. [PMID: 29750857 DOI: 10.1002/anie.201802490] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Indexed: 11/12/2022]
Abstract
Elucidating local dynamics of protein aggregation is crucial for understanding the mechanistic details of protein amyloidogenesis. Herein, we studied the residue-specific dynamics and local environmental changes of Aβ40 along the course of aggregation by using para-cyanophenylalanine (PheCN ) as a fluorescent and vibrational probe. Our results show that the PheCN residues introduced at various positions all exhibited an immediate decay of fluorescence intensity, indicating a relatively synergistic process in early oligomer formation. The fast decreases in the fluorescence intensities of residues 19 and 20 in the central hydrophobic core region and residue 10 in the N-terminal region suggest that they play crucial roles in the formation of the oligomeric core. The PheCN 4 residue exhibits a remarkably slower decrease in fluorescence intensity, implicating its dynamic conformational characteristics in oligomer and fibril formation. Our results also suggest that the N-terminal residues in fibrils are surrounded by a relatively hydrophobic local environment, as opposed to being solvated.
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Affiliation(s)
- Haiyang Liu
- Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Clifford Morris
- Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Richard Lantz
- Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Thomas W Kent
- Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Esmail A Elbassal
- Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Ewa P Wojcikiewicz
- Department of Biomedical Science, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
| | - Deguo Du
- Department of Chemistry and Biochemistry, Florida Atlantic University, 777 Glades Road, Boca Raton, FL, 33431, USA
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14
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Abstract
Our understanding of the complex molecular processes of living organisms at the molecular level is growing exponentially. This knowledge, together with a powerful arsenal of tools for manipulating the structures of macromolecules, is allowing chemists to to harness and reprogram the cellular machinery in ways previously unimaged. Here we review one example in which the genetic code itself has been expanded with new building blocks that allow us to probe and manipulate the structures and functions of proteins with unprecedented precision.
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Affiliation(s)
- Douglas D. Young
- Department of Chemistry, College of William & Mary,
P.O. Box 8795, Williamsburg, VA 23187 (USA)
| | - Peter G. Schultz
- Department of Chemistry, The Scripps Research Institute,
La Jolla, CA 92037 (USA),
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15
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Kearney C, Olenginski LT, Hirn TD, Fowler GD, Tariq D, Brewer SH, Phillips-Piro CM. Exploring local solvation environments of a heme protein using the spectroscopic reporter 4-cyano-l-phenylalanine. RSC Adv 2018; 8:13503-13512. [PMID: 29780583 PMCID: PMC5944249 DOI: 10.1039/c8ra02000k] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 03/20/2018] [Indexed: 11/21/2022] Open
Abstract
The vibrational reporter unnatural amino acid (UAA) 4-cyano-l-phenylalanine (pCNF) was genetically incorporated individually at three sites (5, 36, and 78) in the heme protein Caldanaerobacter subterraneus H-NOX to probe local hydration environments. The UAA pCNF was incorporated site-specifically using an engineered, orthogonal tRNA synthetase in E. coli. The ability of all of the pCNF-containing H-NOX proteins to form the ferrous CO, NO, or O2 ligated and unligated states was confirmed with UV-Vis spectroscopy. The solvation state at each site of the three sites of pCNF incorporation was assessed using temperature-dependent infrared spectroscopy. Specifically, the frequency-temperature line slope (FTLS) method was utilized to show that the nitrile group at site 36 was fully solvated and the nitrile group at site 78 was de-solvated (buried) in the heme pocket. The nitrile group at site 5 was found to be partially solvated suggesting that the nitrile group was involved in moderate strength hydrogen bonds. These results were confirmed by the determination of the X-ray crystal structure of the H-NOX protein construct containing pCNF at site 5.
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Affiliation(s)
- Caroline Kearney
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA. ;
| | - Lukasz T Olenginski
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA. ;
| | - Trexler D Hirn
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA. ;
| | - Gwendolyn D Fowler
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA. ;
| | - Daniyal Tariq
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA. ;
| | - Scott H Brewer
- Department of Chemistry, Franklin & Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA. ;
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16
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Lee G, Kossowska D, Lim J, Kim S, Han H, Kwak K, Cho M. Cyanamide as an Infrared Reporter: Comparison of Vibrational Properties between Nitriles Bonded to N and C Atoms. J Phys Chem B 2018. [DOI: 10.1021/acs.jpcb.8b00887] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Giseong Lee
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Dorota Kossowska
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Joonhyung Lim
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Soobin Kim
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
| | - Hogyu Han
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Kyungwon Kwak
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
- Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Minhaeng Cho
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic Science (IBS), Seoul 02841, Korea
- Department of Chemistry, Korea University, Seoul 02841, Korea
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17
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Martin JP, Fetto NR, Tucker MJ. Comparison of biological chromophores: photophysical properties of cyanophenylalanine derivatives. Phys Chem Chem Phys 2018; 18:20750-7. [PMID: 27412819 DOI: 10.1039/c6cp04154j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Within this work, the family of cyanophenylalanine spectroscopic reporters is extended by showing the ortho and meta derivatives have intrinsic photophysical properties that are useful for studies of protein structure and dynamics. The molar absorptivities of 2-cyanophenylalanine and 3-cyanophenylalanine are shown to be comparable to that of 4-cyanophenylalanine with similar spectral features in their absorbance and emission profiles, demonstrating that these probes can be utilized interchangeably. The fluorescence quantum yields are also on the same scale as commonly used fluorophores in peptides and proteins, tyrosine and tryptophan. These new cyano-fluorophores can be paired with either 4-cyanophenylalanine or tryptophan to capture distances in peptide structure through Förster resonance energy transfer. Additionally, the spectroscopic properties of these chromophores can report the local solvent environment via changes in fluorescence emission intensity as a result of hydrogen bonding and/or hydration. A decrease in the quantum yield is also observed in basic environments due to photoinduced electron transfer from a deprotonated amine in the free PheCN species and at the N-terminus of a short peptide, providing an avenue to detect pH in biological systems. Our results show the potential of these probes, 2-cyanophenylalanine and 3-cyanophenylalanine, to be incorporated into a single peptide chain, either individually or in tandem with 4-cyanophenylalanine, tryptophan, or tyrosine, in order to obtain information about peptide structure and dynamics.
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Affiliation(s)
- Joshua P Martin
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
| | - Natalie R Fetto
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
| | - Matthew J Tucker
- Department of Chemistry, University of Nevada, Reno, 89557, USA.
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18
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van Wilderen LJGW, Brunst H, Gustmann H, Wachtveitl J, Broos J, Bredenbeck J. Cyano-tryptophans as dual infrared and fluorescence spectroscopic labels to assess structural dynamics in proteins. Phys Chem Chem Phys 2018; 20:19906-19915. [DOI: 10.1039/c8cp00846a] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
By moving the cyano group position on the indole ring, both artificial amino acids report differently to their microscopic environment.
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Affiliation(s)
| | - H. Brunst
- Institute of Biophysics
- Johann-Wolfgang-Goethe Universität
- Frankfurt am Main
- Germany
| | - H. Gustmann
- Institute of Physical and Theoretical Chemistry
- Johann-Wolfgang-Goethe Universität
- Frankfurt am Main
- Germany
| | - J. Wachtveitl
- Institute of Physical and Theoretical Chemistry
- Johann-Wolfgang-Goethe Universität
- Frankfurt am Main
- Germany
| | - J. Broos
- Laboratory of Biophysical Chemistry and GBB (Groningen Biomolecular Science and Biotechnology Institute)
- University of Groningen
- 9747 AG Groningen
- The Netherlands
| | - J. Bredenbeck
- Institute of Biophysics
- Johann-Wolfgang-Goethe Universität
- Frankfurt am Main
- Germany
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19
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Fetto NR, Cao W, Wallace IS, Tucker MJ. Selective Excitation of Cyanophenylalanine Fluorophores for Multi-Site Binding Studies. J Phys Chem B 2017; 121:9566-9571. [PMID: 28949137 DOI: 10.1021/acs.jpcb.7b08442] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Recently, it has been shown that nitrile-derivatized phenylalanines possess distinct fluorescent properties depending on the position of the cyano-group within the aromatic ring. These fluorophores have potential as probes for studying protein dynamics due to their sensitivity to local environment. Herein, we demonstrate that 2-cyanophenylalanine (Phe2CN) and Phe4CN can independently monitor multiple sites during the Ca2+ dependent binding of a skeletal muscle myosin light chain kinase (MLCK) peptide fragment to the protein calmodulin (CaM). These cyano-probes were incorporated at two different positions along the peptide chain and monitored simultaneously via selective excitation of the two chromophores. The peptide was labeled with Phe4CN at a residue known to bind to a hydrophobic binding pocket of CaM, while Phe2CN was designed to acquire dynamics external to the binding pocket. By selectively exciting each of the chromophores, it was determined that the fluorescence emission of Phe4CN located at position 581 of MLCK was quenched in the presence of CaM, while no significant change in Phe2CN emission was observed at exposed position 594. The CaM binding affinity (Kd) of the double labeled MLCK peptide was calculated to be approximately 64 nM, which is in agreement with previous measurements. These results indicate that multiple PheCN reporters within the same peptide can simultaneously detect variations in the local environment, and that these fluorophores could be utilized to investigate a wide variety of biological problems.
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Affiliation(s)
- Natalie R Fetto
- Department of Chemistry, University of Nevada , 1664 North Virginia Street, Reno, Nevada 89557, United States
| | - Wenqiang Cao
- Department of Chemistry, University of Nevada , 1664 North Virginia Street, Reno, Nevada 89557, United States
| | - Ian S Wallace
- Department of Chemistry, University of Nevada , 1664 North Virginia Street, Reno, Nevada 89557, United States.,Department of Biochemistry and Molecular Biology, University of Nevada , 1664 North Virginia Street, Reno, Nevada 89557, United States
| | - Matthew J Tucker
- Department of Chemistry, University of Nevada , 1664 North Virginia Street, Reno, Nevada 89557, United States
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20
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Adhikary R, Zimmermann J, Romesberg FE. Transparent Window Vibrational Probes for the Characterization of Proteins With High Structural and Temporal Resolution. Chem Rev 2017; 117:1927-1969. [DOI: 10.1021/acs.chemrev.6b00625] [Citation(s) in RCA: 83] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Ramkrishna Adhikary
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Jörg Zimmermann
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
| | - Floyd E. Romesberg
- Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037, United States
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21
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Ries LK, Schmid FX, Schmidpeter PAM. Incorporation of an Unnatural Amino Acid as a Domain-Specific Fluorescence Probe in a Two-Domain Protein. Biochemistry 2016; 55:6739-6742. [DOI: 10.1021/acs.biochem.6b00898] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lena K. Ries
- Laboratorium für Biochemie
und Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstraße 30, D-95447 Bayreuth, Germany
| | - Franz X. Schmid
- Laboratorium für Biochemie
und Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstraße 30, D-95447 Bayreuth, Germany
| | - Philipp A. M. Schmidpeter
- Laboratorium für Biochemie
und Bayreuther Zentrum für Molekulare Biowissenschaften, Universität Bayreuth, Universitätsstraße 30, D-95447 Bayreuth, Germany
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22
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Xiao H, Schultz PG. At the Interface of Chemical and Biological Synthesis: An Expanded Genetic Code. Cold Spring Harb Perspect Biol 2016; 8:cshperspect.a023945. [PMID: 27413101 DOI: 10.1101/cshperspect.a023945] [Citation(s) in RCA: 102] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The ability to site-specifically incorporate noncanonical amino acids (ncAAs) with novel structures into proteins in living cells affords a powerful tool to investigate and manipulate protein structure and function. More than 200 ncAAs with diverse biological, chemical, and physical properties have been genetically encoded in response to nonsense or frameshift codons in both prokaryotic and eukaryotic organisms with high fidelity and efficiency. In this review, recent advances in the technology and its application to problems in protein biochemistry, cellular biology, and medicine are highlighted.
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Affiliation(s)
- Han Xiao
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037
| | - Peter G Schultz
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, La Jolla, California 92037 California Institute for Biomedical Research, La Jolla, California 92037
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23
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Maj M, Ahn C, Błasiak B, Kwak K, Han H, Cho M. Isonitrile as an Ultrasensitive Infrared Reporter of Hydrogen-Bonding Structure and Dynamics. J Phys Chem B 2016; 120:10167-10180. [DOI: 10.1021/acs.jpcb.6b04319] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Affiliation(s)
- Michał Maj
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic
Science (IBS) and ‡Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Changwoo Ahn
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic
Science (IBS) and ‡Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Bartosz Błasiak
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic
Science (IBS) and ‡Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Kyungwon Kwak
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic
Science (IBS) and ‡Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Hogyu Han
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic
Science (IBS) and ‡Department of Chemistry, Korea University, Seoul 02841, Korea
| | - Minhaeng Cho
- Center for Molecular Spectroscopy and Dynamics, Institute for Basic
Science (IBS) and ‡Department of Chemistry, Korea University, Seoul 02841, Korea
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24
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Watson MD, Peran I, Raleigh DP. A Non-perturbing Probe of Coiled Coil Formation Based on Electron Transfer Mediated Fluorescence Quenching. Biochemistry 2016; 55:3685-91. [PMID: 27258904 DOI: 10.1021/acs.biochem.6b00270] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Coiled coils are abundant in nature, occurring in ∼3% of proteins across sequenced genomes, and are found in proteins ranging from transcription factors to structural proteins. The motif continues to be an important model system for understanding protein-protein interactions and is finding increased use in bioinspired materials and synthetic biology. Knowledge of the thermodynamics of self-assembly, particularly the dissociation constant KD, is essential for the application of designed coiled coils and for understanding the in vivo specificity of natural coiled coils. Standard methods for measuring KD typically rely on concentration dependent circular dichroism (CD). Fluorescence methods are an attractive alternative; however Trp is rarely found in an interior position of a coiled coil, and appending unnatural fluorophores can perturb the system. We demonstrate a simple, non-perturbing method to monitor coiled coil formation using p-cyanophenylalanine (FCN) and selenomethionine (MSe), the Se analogue of Met. FCN fluorescence can be selectively excited and is effectively quenched by electron transfer with MSe. Both FCN and MSe represent minimally perturbing substitutions in coiled coils. MSe quenching of FCN fluorescence is shown to offer a non-perturbing method for following coiled coil formation and for accurately determining dissociation constants. The method is validated using a designed heterodimeric coiled coil. The KD deduced by fluorescence monitored titration is in excellent agreement with the value deduced from concentration dependent CD measurements to within the uncertainty of the measurement. However, the fluorescence approach requires less protein, is less time-consuming, can be applied to lower concentrations and could be applied to high throughput screens.
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Affiliation(s)
- Matthew D Watson
- Department of Chemistry and ‡Graduate Program in Biochemistry & Structural Biology, Stony Brook University , Stony Brook, New York 11794-3400, United States
| | - Ivan Peran
- Department of Chemistry and ‡Graduate Program in Biochemistry & Structural Biology, Stony Brook University , Stony Brook, New York 11794-3400, United States
| | - Daniel P Raleigh
- Department of Chemistry and ‡Graduate Program in Biochemistry & Structural Biology, Stony Brook University , Stony Brook, New York 11794-3400, United States
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25
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Mohrmann H, Kube I, Lórenz-Fonfría VA, Engelhard M, Heberle J. Transient Conformational Changes of Sensory Rhodopsin II Investigated by Vibrational Stark Effect Probes. J Phys Chem B 2016; 120:4383-7. [DOI: 10.1021/acs.jpcb.6b01900] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Hendrik Mohrmann
- Department
of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Ines Kube
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Víctor A. Lórenz-Fonfría
- Department
of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
| | - Martin Engelhard
- Max Planck Institute of Molecular Physiology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Joachim Heberle
- Department
of Physics, Experimental Molecular Biophysics, Freie Universität Berlin, 14195 Berlin, Germany
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26
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Wang YJ, Szantai-Kis DM, Petersson EJ. Semi-synthesis of thioamide containing proteins. Org Biomol Chem 2016; 13:5074-81. [PMID: 25811732 DOI: 10.1039/c5ob00224a] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Our laboratory has shown that the thioamide, a single atom O-to-S substitution, can be a versatile fluorescence quenching probe that is minimally-perturbing when placed at many locations in a protein sequence. In order to make these and other thioamide experiments applicable to full-sized proteins, we have developed methods for incorporating thioamides by generating thiopeptide fragments through solid phase synthesis and ligating them to protein fragments expressed in E. coli. To install donor fluorophores, we have adapted unnatural amino acid mutagenesis methods, including the generation of new tRNA synthetases for the incorporation of small, intrinsically fluorescent amino acids. We have used a combination of these two methods, as well as chemoenzymatic protein modification, to efficiently install sidechain and backbone modifications to generate proteins labeled with fluorophore/thioamide pairs.
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Affiliation(s)
- Yanxin J Wang
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA.
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27
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Dippel AB, Olenginski GM, Maurici N, Liskov MT, Brewer SH, Phillips-Piro CM. Probing the effectiveness of spectroscopic reporter unnatural amino acids: a structural study. Acta Crystallogr D Struct Biol 2016; 72:121-30. [PMID: 26894540 PMCID: PMC4756619 DOI: 10.1107/s2059798315022858] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2015] [Accepted: 11/29/2015] [Indexed: 11/10/2022] Open
Abstract
The X-ray crystal structures of superfolder green fluorescent protein (sfGFP) containing the spectroscopic reporter unnatural amino acids (UAAs) 4-cyano-L-phenylalanine (pCNF) or 4-ethynyl-L-phenylalanine (pCCF) at two unique sites in the protein have been determined. These UAAs were genetically incorporated into sfGFP in a solvent-exposed loop region and/or a partially buried site on the β-barrel of the protein. The crystal structures containing the UAAs at these two sites permit the structural implications of UAA incorporation for the native protein structure to be assessed with high resolution and permit a direct correlation between the structure and spectroscopic data to be made. The structural implications were quantified by comparing the root-mean-square deviation (r.m.s.d.) between the crystal structure of wild-type sfGFP and the protein constructs containing either pCNF or pCCF in the local environment around the UAAs and in the overall protein structure. The results suggest that the selective placement of these spectroscopic reporter UAAs permits local protein environments to be studied in a relatively nonperturbative fashion with site-specificity.
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Affiliation(s)
- Andrew B. Dippel
- Department of Chemistry, Franklin and Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA
| | - Gregory M. Olenginski
- Department of Chemistry, Franklin and Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA
| | - Nicole Maurici
- Department of Chemistry, Franklin and Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA
| | - Melanie T. Liskov
- Department of Chemistry, Franklin and Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA
| | - Scott H. Brewer
- Department of Chemistry, Franklin and Marshall College, PO Box 3003, Lancaster, PA 17604-3003, USA
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28
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Ritchie AW, Webb LJ. Understanding and Manipulating Electrostatic Fields at the Protein-Protein Interface Using Vibrational Spectroscopy and Continuum Electrostatics Calculations. J Phys Chem B 2015; 119:13945-57. [PMID: 26375183 DOI: 10.1021/acs.jpcb.5b06888] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Biological function emerges in large part from the interactions of biomacromolecules in the complex and dynamic environment of the living cell. For this reason, macromolecular interactions in biological systems are now a major focus of interest throughout the biochemical and biophysical communities. The affinity and specificity of macromolecular interactions are the result of both structural and electrostatic factors. Significant advances have been made in characterizing structural features of stable protein-protein interfaces through the techniques of modern structural biology, but much less is understood about how electrostatic factors promote and stabilize specific functional macromolecular interactions over all possible choices presented to a given molecule in a crowded environment. In this Feature Article, we describe how vibrational Stark effect (VSE) spectroscopy is being applied to measure electrostatic fields at protein-protein interfaces, focusing on measurements of guanosine triphosphate (GTP)-binding proteins of the Ras superfamily binding with structurally related but functionally distinct downstream effector proteins. In VSE spectroscopy, spectral shifts of a probe oscillator's energy are related directly to that probe's local electrostatic environment. By performing this experiment repeatedly throughout a protein-protein interface, an experimental map of measured electrostatic fields generated at that interface is determined. These data can be used to rationalize selective binding of similarly structured proteins in both in vitro and in vivo environments. Furthermore, these data can be used to compare to computational predictions of electrostatic fields to explore the level of simulation detail that is necessary to accurately predict our experimental findings.
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Affiliation(s)
- Andrew W Ritchie
- Department of Chemistry, Center for Nano- and Molecular Science and Technology, and Institute for Cell and Molecular Biology, The University of Texas at Austin , 105 East 24th Street STOP A5300, Austin, Texas 78712, United States
| | - Lauren J Webb
- Department of Chemistry, Center for Nano- and Molecular Science and Technology, and Institute for Cell and Molecular Biology, The University of Texas at Austin , 105 East 24th Street STOP A5300, Austin, Texas 78712, United States
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29
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Pazos IM, Ahmed IA, Berríos MIL, Gai F. Sensing pH via p-cyanophenylalanine fluorescence: Application to determine peptide pKa and membrane penetration kinetics. Anal Biochem 2015; 483:21-6. [PMID: 25935260 DOI: 10.1016/j.ab.2015.04.026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 04/23/2015] [Accepted: 04/24/2015] [Indexed: 12/22/2022]
Abstract
We expand the spectroscopic utility of a well-known infrared and fluorescence probe, p-cyanophenylalanine, by showing that it can also serve as a pH sensor. This new application is based on the notion that the fluorescence quantum yield of this unnatural amino acid, when placed at or near the N-terminal end of a polypeptide, depends on the protonation status of the N-terminal amino group of the peptide. Using this pH sensor, we are able to determine the N-terminal pKa values of nine tripeptides and also the membrane penetration kinetics of a cell-penetrating peptide. Taken together, these examples demonstrate the applicability of using this unnatural amino acid fluorophore to study pH-dependent biological processes or events that accompany a pH change.
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Affiliation(s)
- Ileana M Pazos
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Ismail A Ahmed
- Department of Biochemistry and Biophysics, University of Pennsylvania, Philadelphia, PA 19104, USA
| | | | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
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30
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Mintzer MR, Troxler T, Gai F. p-Cyanophenylalanine and selenomethionine constitute a useful fluorophore-quencher pair for short distance measurements: application to polyproline peptides. Phys Chem Chem Phys 2015; 17:7881-7. [PMID: 25716887 PMCID: PMC4357573 DOI: 10.1039/c5cp00050e] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The C≡N stretching frequency and fluorescence quantum yield of p-cyanophenylalanine are sensitive to environment. As such, this unnatural amino acid has found broad applications, ranging from studying how proteins fold to determining the local electric field of membranes. Herein, we demonstrate that the fluorescence of p-cyanophenylalanine can be quenched by selenomethionine through an electron transfer process occurring at short distances, thus further expanding its spectroscopic utility. Using this fluorophore-quencher pair, we are able to show that short polyproline peptides (1-4 prolines) are not rigid; instead, they sample a bimodal conformational distribution.
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Affiliation(s)
- Mary Rose Mintzer
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Thomas Troxler
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
- The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
- The Ultrafast Optical Processes Laboratory, University of Pennsylvania, Philadelphia, PA 19104
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31
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Batjargal S, Walters CR, Petersson EJ. Inteins as traceless purification tags for unnatural amino acid proteins. J Am Chem Soc 2015; 137:1734-7. [PMID: 25625321 DOI: 10.1021/ja5103019] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The expression of proteins containing unnatural amino acids through suppression of a stop codon can be limited by truncation due to competition with release factors. When the site of incorporation is near the C-terminus, it may not be feasible to separate the full-length unnatural amino acid protein from the truncated form. We report a simple, traceless procedure that allows one to isolate the desired protein using a C-terminal intein fusion.
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Affiliation(s)
- Solongo Batjargal
- Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104, United States
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32
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Liu H, Lantz R, Cosme P, Rivera N, Andino C, Gonzalez WG, Terentis AC, Wojcikiewicz EP, Oyola R, Miksovska J, Du D. Site-specific dynamics of amyloid formation and fibrillar configuration of Aβ1–23 using an unnatural amino acid. Chem Commun (Camb) 2015; 51:7000-3. [DOI: 10.1039/c5cc00149h] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Distinct local dynamics of Aβ1–23 amyloid formation are characterized using an unnatural amino acid p-cyanophenylalanine as a spectroscopic probe.
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Affiliation(s)
- Haiyang Liu
- Department of Chemistry and Biochemistry
- Florida Atlantic University
- Boca Raton
- USA
| | - Richard Lantz
- Department of Chemistry and Biochemistry
- Florida Atlantic University
- Boca Raton
- USA
| | - Patrick Cosme
- Department of Chemistry and Biochemistry
- Florida Atlantic University
- Boca Raton
- USA
| | - Nelson Rivera
- Department of Chemistry
- University of Puerto Rico-Humacao
- Humacao
- Puerto Rico
| | - Carlos Andino
- Department of Chemistry
- University of Puerto Rico-Humacao
- Humacao
- Puerto Rico
| | - Walter G. Gonzalez
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
| | - Andrew C. Terentis
- Department of Chemistry and Biochemistry
- Florida Atlantic University
- Boca Raton
- USA
| | | | - Rolando Oyola
- Department of Chemistry
- University of Puerto Rico-Humacao
- Humacao
- Puerto Rico
| | - Jaroslava Miksovska
- Department of Chemistry and Biochemistry
- Florida International University
- Miami
- USA
| | - Deguo Du
- Department of Chemistry and Biochemistry
- Florida Atlantic University
- Boca Raton
- USA
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33
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Maj M, Ahn C, Kossowska D, Park K, Kwak K, Han H, Cho M. β-Isocyanoalanine as an IR probe: comparison of vibrational dynamics between isonitrile and nitrile-derivatized IR probes. Phys Chem Chem Phys 2015; 17:11770-8. [DOI: 10.1039/c5cp00454c] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An infrared (IR) probe based on isonitrile (NC)-derivatized alanine 1 was synthesized and the vibrational properties of its NC stretching mode were investigated using FTIR and femtosecond IR pump–probe spectroscopy.
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Affiliation(s)
- Michał Maj
- Center for Molecular Spectroscopy and Dynamics
- Institute for Basic Science (IBS)
- Seoul 136-701, Korea
- Department of Chemistry
- Korea University
| | - Changwoo Ahn
- Department of Chemistry
- Korea University
- Seoul 136-701, Korea
| | - Dorota Kossowska
- Center for Molecular Spectroscopy and Dynamics
- Institute for Basic Science (IBS)
- Seoul 136-701, Korea
- Department of Chemistry
- Korea University
| | - Kwanghee Park
- Center for Molecular Spectroscopy and Dynamics
- Institute for Basic Science (IBS)
- Seoul 136-701, Korea
- Department of Chemistry
- Korea University
| | - Kyungwon Kwak
- Department of Chemistry
- Chung-Ang University
- Seoul 156-756, Korea
| | - Hogyu Han
- Department of Chemistry
- Korea University
- Seoul 136-701, Korea
| | - Minhaeng Cho
- Center for Molecular Spectroscopy and Dynamics
- Institute for Basic Science (IBS)
- Seoul 136-701, Korea
- Department of Chemistry
- Korea University
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34
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Horness RE, Basom EJ, Thielges MC. Site-selective Characterization of Src Homology 3 Domain Molecular Recognition with Cyanophenylalanine Infrared Probes. ANALYTICAL METHODS : ADVANCING METHODS AND APPLICATIONS 2015; 7:7234-7241. [PMID: 26491469 PMCID: PMC4609639 DOI: 10.1039/c5ay00523j] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Local heterogeneity of microenvironments in proteins is important in biological function, but difficult to characterize experimentally. One approach is the combination of infrared (IR) spectroscopy and site-selective incorporation of probe moieties with spectrally resolved IR absorptions that enable characterization within inherently congested protein IR spectra. We employed this method to study molecular recognition of a Src homology 3 (SH3) domain from the yeast protein Sho1 for a peptide containing the proline-rich recognition sequence of its physiological binding partner Pbs2. Nitrile IR probes were introduced at four distinct sites in the protein by selective incorporation of p-cyanophenylalanine via the amber codon suppressor method and characterized by IR spectroscopy. Variation among the IR absorption bands reports on heterogeneity in local residue environments dictated by the protein structure, as well as on residue-dependent changes upon peptide binding. The study informs on the molecular recognition of SH3 Sho1 and illustrates the speed and simplicity of this approach for characterization of select microenvironments within proteins.
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Affiliation(s)
| | - Edward J. Basom
- Department of Chemistry, Indiana University, Bloomington, USA
| | - Megan C. Thielges
- Department of Chemistry, Indiana University, Bloomington, USA
- Corresponding authors,
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35
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Dumas A, Lercher L, Spicer CD, Davis BG. Designing logical codon reassignment - Expanding the chemistry in biology. Chem Sci 2015; 6:50-69. [PMID: 28553457 PMCID: PMC5424465 DOI: 10.1039/c4sc01534g] [Citation(s) in RCA: 327] [Impact Index Per Article: 36.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2014] [Accepted: 07/14/2014] [Indexed: 12/18/2022] Open
Abstract
Over the last decade, the ability to genetically encode unnatural amino acids (UAAs) has evolved rapidly. The programmed incorporation of UAAs into recombinant proteins relies on the reassignment or suppression of canonical codons with an amino-acyl tRNA synthetase/tRNA (aaRS/tRNA) pair, selective for the UAA of choice. In order to achieve selective incorporation, the aaRS should be selective for the designed tRNA and UAA over the endogenous amino acids and tRNAs. Enhanced selectivity has been achieved by transferring an aaRS/tRNA pair from another kingdom to the organism of interest, and subsequent aaRS evolution to acquire enhanced selectivity for the desired UAA. Today, over 150 non-canonical amino acids have been incorporated using such methods. This enables the introduction of a large variety of structures into proteins, in organisms ranging from prokaryote, yeast and mammalian cells lines to whole animals, enabling the study of protein function at a level that could not previously be achieved. While most research to date has focused on the suppression of 'non-sense' codons, recent developments are beginning to open up the possibility of quadruplet codon decoding and the more selective reassignment of sense codons, offering a potentially powerful tool for incorporating multiple amino acids. Here, we aim to provide a focused review of methods for UAA incorporation with an emphasis in particular on the different tRNA synthetase/tRNA pairs exploited or developed, focusing upon the different UAA structures that have been incorporated and the logic behind the design and future creation of such systems. Our hope is that this will help rationalize the design of systems for incorporation of unexplored unnatural amino acids, as well as novel applications for those already known.
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Affiliation(s)
- Anaëlle Dumas
- Chemistry Research Laboratory , Department of Chemistry , University of Oxford , Mansfield Road , Oxford , OX1 3TA , UK .
| | - Lukas Lercher
- Chemistry Research Laboratory , Department of Chemistry , University of Oxford , Mansfield Road , Oxford , OX1 3TA , UK .
| | - Christopher D Spicer
- Chemistry Research Laboratory , Department of Chemistry , University of Oxford , Mansfield Road , Oxford , OX1 3TA , UK .
| | - Benjamin G Davis
- Chemistry Research Laboratory , Department of Chemistry , University of Oxford , Mansfield Road , Oxford , OX1 3TA , UK .
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36
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Tookmanian EM, Fenlon EE, Brewer SH. Synthesis and Protein Incorporation of Azido-Modified Unnatural Amino Acids. RSC Adv 2014; 5:1274-1281. [PMID: 26478813 PMCID: PMC4603873 DOI: 10.1039/c4ra14244f] [Citation(s) in RCA: 84] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Two new azidophenylalanine residues (3 and 4) have been synthesized and, in combination with 4-azido-L-phenylalanine (1) and 4-azidomethyl-L-phenylalanine (2), form a series of unnatural amino acids (UAAs) containing the azide vibrational reporter at varying distances from the aromatic ring of phenylalanine. These UAAs were designed to probe protein hydration with high spatial resolution by utilizing the large extinction coefficient and environmental sensitivity of the azide asymmetric stretch vibration. The sensitivity of the azide reporters was investigated in solvents that mimic distinct local protein environments. Three of the four azido-modified phenylalanine residues were successfully genetically incorporated into a surface site in superfolder green fluorescent protein (sfGFP) utilizing an engineered, orthogonal aminoacyl-tRNA synthetase in response to an amber codon with high efficiency and fidelity. SDS-PAGE and ESI-Q-TOF mass analysis verified the site-specific incorporation of these UAAs. The observed azide asymmetric stretch in the linear IR spectra of these UAAs incorporated into sfGFP indicated that the azide groups were hydrated in the protein.
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Affiliation(s)
- Elise M. Tookmanian
- Franklin & Marshall College, Department of Chemistry, Lancaster, PA 17604-3003 USA
| | - Edward E. Fenlon
- Franklin & Marshall College, Department of Chemistry, Lancaster, PA 17604-3003 USA
| | - Scott H. Brewer
- Franklin & Marshall College, Department of Chemistry, Lancaster, PA 17604-3003 USA
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37
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Meloni SL, Matsika S. Theoretical studies of the excited states of p-cyanophenylalanine and comparisons with the natural amino acids phenylalanine and tyrosine. Theor Chem Acc 2014. [DOI: 10.1007/s00214-014-1497-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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38
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Tharp JM, Wang YS, Lee YJ, Yang Y, Liu WR. Genetic incorporation of seven ortho-substituted phenylalanine derivatives. ACS Chem Biol 2014; 9:884-90. [PMID: 24451054 PMCID: PMC3997995 DOI: 10.1021/cb400917a] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
![]()
Seven
phenylalanine derivatives with small ortho substitutions
were genetically encoded in Escherichia coli and
mammalian cells at an amber codon using a previously reported,
rationally designed pyrrolysyl-tRNA synthetase mutant (PylRS(N346A/C348A))
coupled with tRNACUAPyl. Ortho substitutions of the phenylalanine
derivatives reported herein include three halides, methyl, methoxy,
nitro, and nitrile. These compounds have the potential for use in
multiple biochemical and biophysical applications. Specifically, we
demonstrated that o-cyano-phenylalanine could be
used as a selective sensor to probe the local environment of proteins
and applied this to study protein folding/unfolding. For six of these
compounds this constitutes the first report of their genetic incorporation
in living cells. With these compounds the total number of substrates
available for PylRS(N346A/C348A) is increased to nearly 40, which
demonstrates that PylRS(N346A/C348A) is able to recognize phenylalanine
with a substitution at any side-chain aromatic position as a substrate.
To our knowledge, PylRS(N346A/C348A) is the only aminoacyl-tRNA synthetase
with such a high substrate promiscuity.
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Affiliation(s)
- Jeffery M. Tharp
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Yane-Shih Wang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Yan-Jiun Lee
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Yanyan Yang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Wenshe R. Liu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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39
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Abstract
Genetic code expansion and reprogramming enable the site-specific incorporation of diverse designer amino acids into proteins produced in cells and animals. Recent advances are enhancing the efficiency of unnatural amino acid incorporation by creating and evolving orthogonal ribosomes and manipulating the genome. Increasing the number of distinct amino acids that can be site-specifically encoded has been facilitated by the evolution of orthogonal quadruplet decoding ribosomes and the discovery of mutually orthogonal synthetase/tRNA pairs. Rapid progress in moving genetic code expansion from bacteria to eukaryotic cells and animals (C. elegans and D. melanogaster) and the incorporation of useful unnatural amino acids has been aided by the development and application of the pyrrolysyl-transfer RNA (tRNA) synthetase/tRNA pair for unnatural amino acid incorporation. Combining chemoselective reactions with encoded amino acids has facilitated the installation of posttranslational modifications, as well as rapid derivatization with diverse fluorophores for imaging.
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Affiliation(s)
- Jason W Chin
- Medical Research Council Laboratory of Molecular Biology, Cambridge CB2 OQH, United Kingdom;
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40
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Yaşar F, Jiang P, Hansmann UHE. Multicanonical Molecular Dynamics Simulations of the N-terminal Domain of Protein L9. EUROPHYSICS LETTERS 2014; 105:30008. [PMID: 25253918 PMCID: PMC4169893 DOI: 10.1209/0295-5075/105/30008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
We describe multicanonical molecular dynamic simulations of the N-terminal domain of the protein L9. Analyzing free energy landscapes and thermal ordering, we propose a possible folding mechanism for the protein. By comparing our results with that of molecular dynamics runs of the protein at constant temperature, we find that multicanonical molecular dynamics leads to orders of magnitude higher sampling of folding transitions.
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Affiliation(s)
- Fatih Yaşar
- Department of Physics Engineering, Hacettepe University, Ankara, 06800, TURKEY
| | - Ping Jiang
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, OK 73019-5251, USA
| | - Ulrich H. E. Hansmann
- Department of Chemistry & Biochemistry, University of Oklahoma, Norman, OK 73019-5251, USA
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41
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Speight LC, Samanta M, Petersson EJ. Minimalist Approaches to Protein Labelling: Getting the Most Fluorescent Bang for Your Steric Buck. Aust J Chem 2014. [DOI: 10.1071/ch13554] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Fluorescence methods allow one to monitor protein conformational changes, protein–protein associations, and proteolysis in real time, at the single molecule level and in living cells. The information gained in such experiments is a function of the spectroscopic techniques used and the strategic placement of fluorophore labels within the protein structure. There is often a trade-off between size and utility for fluorophores, whereby large size can be disruptive to the protein’s fold or function, but valuable characteristics, such as visible wavelength absorption and emission or brightness, require sizable chromophores. Three major types of fluorophore readouts are commonly used: (1) Förster resonance energy transfer (FRET); (2) photoinduced electron transfer (PET); and (3) environmental sensitivity. This review focuses on those probes small enough to be incorporated into proteins during ribosomal translation, which allows the probes to be placed on the interiors of proteins as they are folded during synthesis. The most broadly useful method for doing so is site-specific unnatural amino acid (UAA) mutagenesis. We discuss the use of UAA probes in applications relying on FRET, PET, and environmental sensitivity. We also briefly review other methods of protein labelling and compare their relative merits to UAA mutagenesis. Finally, we discuss small probes that have thus far been used only in synthetic peptides, but which have unusual value and may be candidates for incorporation using UAA methods.
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42
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Gonzalez JD, Levonyak NS, Schneider SC, Smith MJ, Cremeens ME. Using infrared spectroscopy of a nitrile labeled phenylalanine and tryptophan fluorescence to probe the α-MSH peptide’s side-chain interactions with a micelle model membrane. J Mol Struct 2014. [DOI: 10.1016/j.molstruc.2013.09.059] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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43
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Ding B, Laaser JE, Liu Y, Wang P, Zanni MT, Chen Z. Site-specific orientation of an α-helical peptide ovispirin-1 from isotope-labeled SFG spectroscopy. J Phys Chem B 2013; 117:14625-34. [PMID: 24228619 DOI: 10.1021/jp408064b] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Sum-frequency generation (SFG) vibrational spectroscopy is often used to probe the backbone structures and orientations of polypeptides at surfaces. Using the ovispirin-1 polypeptide at the solid/liquid interface of polystyrene, we demonstrate for the first time that SFG can probe the polarization response of a single-isotope-labeled residue. To interpret the spectral intensities, we simulated the spectra using an excitonic Hamiltonian approach. We show that the polarization dependence of either the label or the unlabeled amide I band alone does not provide sufficient structural constraints to obtain both the tilt and the twist of the ovispirin helix at a solid/liquid interface, but that both can be determined from the polarization dependence of the complete spectrum. For ovispirin, the detailed analysis of the polarized SFG experimental data shows that the helix axis is tilted at roughly 138° from the surface normal, and the transition dipole of the isotope-labeled C═O group is tilted at 23° from the surface normal, with the hydrophobic region facing the polystyrene surface. We further demonstrate that the Hamiltonian approach is able to address the coupling effect and the structural disorder. For comparison, we also collected the FTIR spectrum of ovispirin under similar conditions, which reveals the enhanced sensitivity of SFG for structural studies of single monolayer peptide surfaces. Our study provides insight into how structural and environmental effects appear in SFG spectra of the amide I band and establishes that SFG of isotope-labeled peptides will be a powerful technique for elucidating secondary structures with residue-by-residue resolution.
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Affiliation(s)
- Bei Ding
- Department of Chemistry, University of Michigan , Ann Arbor, Michigan 48109, United States
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44
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Wissner RF, Wagner AM, Warner JB, Petersson EJ. Efficient, Traceless Semi-Synthesis of α-Synuclein Labeled with a Fluorophore/Thioamide FRET Pair. Synlett 2013; 24:2454-2458. [PMID: 26893537 PMCID: PMC4755331 DOI: 10.1055/s-0033-1339853] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We have shown that thioamides can be incorporated into proteins through semi-synthesis and used as probes to monitor structural changes. To date, our methods have required the presence of a cysteine at the peptide ligation site, which may not be present in the native peptide sequence. Here, we present a strategy for the semi-synthesis of thioproteins using homocysteine as a ligation point with subsequent masking as methionine, making the ligation "traceless."
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Affiliation(s)
- Rebecca F. Wissner
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - Anne M. Wagner
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - John B. Warner
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
| | - E. James Petersson
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
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45
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Bazewicz CG, Liskov MT, Hines KJ, Brewer SH. Sensitive, site-specific, and stable vibrational probe of local protein environments: 4-azidomethyl-L-phenylalanine. J Phys Chem B 2013; 117:8987-93. [PMID: 23865850 DOI: 10.1021/jp4052598] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
We have synthesized the unnatural amino acid (UAA), 4-azidomethyl-L-phenylalanine (pN₃CH₂Phe), to serve as an effective vibrational reporter of local protein environments. The position, extinction coefficient, and sensitivity to local environment of the azide asymmetric stretch vibration of pN₃CH₂Phe are compared to the vibrational reporters: 4-cyano-L-phenylalanine (pCNPhe) and 4-azido-L-phenylalanine (pN₃Phe). This UAA was genetically incorporated in a site-specific manner utilizing an engineered, orthogonal aminoacyl-tRNA synthetase in response to an amber codon with high efficiency and fidelity into two distinct sites in superfolder green fluorescent protein (sfGFP). This allowed for the dependence of the azide asymmetric stretch vibration of pN₃CH₂Phe to different protein environments to be measured. The photostability of pN₃CH₂Phe was also measured relative to the photoreactive UAA, pN₃Phe.
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Affiliation(s)
- Christopher G Bazewicz
- Department of Chemistry, Franklin & Marshall College, Lancaster, Pennsylvania 17604-3003, USA
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46
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Wissner RF, Batjargal S, Fadzen CM, Petersson EJ. Labeling proteins with fluorophore/thioamide Förster resonant energy transfer pairs by combining unnatural amino acid mutagenesis and native chemical ligation. J Am Chem Soc 2013; 135:6529-40. [PMID: 23594264 DOI: 10.1021/ja4005943] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have recently shown that p-cyanophenylalanine (Cnf) and a thioamide can be used as a minimally perturbing Förster resonant energy transfer (FRET) pair to monitor protein conformation. We have also shown that thioamide analogues of natural amino acids can be incorporated into full-sized proteins through native chemical ligation. For intermolecular studies with Cnf/thioamide FRET pairs, Cnf can be incorporated into proteins expressed in Escherichia coli through unnatural amino acid mutagenesis using a Cnf-specific tRNA synthetase. For intramolecular studies, a Cnf-labeled protein fragment can be expressed in E. coli and then ligated to a thioamide-labeled peptide synthesized on solid phase. This combination of methods allows for rapid access to double-labeled proteins with a minimum of unnecessary chemical synthesis. We demonstrate the utility of this approach by studying the binding of peptides to the protein calmodulin and by determining the orientation of the N- and C-termini in the amyloidogenic protein α-synuclein.
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Affiliation(s)
- Rebecca F Wissner
- Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA
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Pandey AK, Naduthambi D, Thomas KM, Zondlo NJ. Proline editing: a general and practical approach to the synthesis of functionally and structurally diverse peptides. Analysis of steric versus stereoelectronic effects of 4-substituted prolines on conformation within peptides. J Am Chem Soc 2013; 135:4333-63. [PMID: 23402492 PMCID: PMC4209921 DOI: 10.1021/ja3109664] [Citation(s) in RCA: 138] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Functionalized proline residues have diverse applications. Herein we describe a practical approach, proline editing, for the synthesis of peptides with stereospecifically modified proline residues. Peptides are synthesized by standard solid-phase peptide synthesis to incorporate Fmoc-hydroxyproline (4R-Hyp). In an automated manner, the Hyp hydroxyl is protected and the remainder of the peptide synthesized. After peptide synthesis, the Hyp protecting group is orthogonally removed and Hyp selectively modified to generate substituted proline amino acids, with the peptide main chain functioning to "protect" the proline amino and carboxyl groups. In a model tetrapeptide (Ac-TYPN-NH2), 4R-Hyp was stereospecifically converted to 122 different 4-substituted prolyl amino acids, with 4R or 4S stereochemistry, via Mitsunobu, oxidation, reduction, acylation, and substitution reactions. 4-Substituted prolines synthesized via proline editing include incorporated structured amino acid mimetics (Cys, Asp/Glu, Phe, Lys, Arg, pSer/pThr), recognition motifs (biotin, RGD), electron-withdrawing groups to induce stereoelectronic effects (fluoro, nitrobenzoate), handles for heteronuclear NMR ((19)F:fluoro; pentafluorophenyl or perfluoro-tert-butyl ether; 4,4-difluoro; (77)SePh) and other spectroscopies (fluorescence, IR: cyanophenyl ether), leaving groups (sulfonate, halide, NHS, bromoacetate), and other reactive handles (amine, thiol, thioester, ketone, hydroxylamine, maleimide, acrylate, azide, alkene, alkyne, aryl halide, tetrazine, 1,2-aminothiol). Proline editing provides access to these proline derivatives with no solution-phase synthesis. All peptides were analyzed by NMR to identify stereoelectronic and steric effects on conformation. Proline derivatives were synthesized to permit bioorthogonal conjugation reactions, including azide-alkyne, tetrazine-trans-cyclooctene, oxime, reductive amination, native chemical ligation, Suzuki, Sonogashira, cross-metathesis, and Diels-Alder reactions. These proline derivatives allowed three parallel bioorthogonal reactions to be conducted in one solution.
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Affiliation(s)
- Anil K. Pandey
- Department of Chemistry and Biochemistry, University of Delaware, Newark DE 19716
| | - Devan Naduthambi
- Department of Chemistry and Biochemistry, University of Delaware, Newark DE 19716
| | - Krista M. Thomas
- Department of Chemistry and Biochemistry, University of Delaware, Newark DE 19716
| | - Neal J. Zondlo
- Department of Chemistry and Biochemistry, University of Delaware, Newark DE 19716
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48
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Abstract
To expand the spectroscopic utility of the non-natural amino acid p-cyanophenylalanine (PheCN), we examine the quenching efficiencies of a series of commonly encountered anions toward its fluorescence. We find that iodide exhibits an unusually large Stern-Volmer quenching constant, making it a convenient choice in PheCN fluorescence quenching studies. Indeed, using the villin headpiece subdomain as a testbed we demonstrate that iodide quenching of PheCN fluorescence offers a convenient means to reveal protein conformational heterogeneity. Furthermore, we show that the amino group of PheCN strongly quenches its fluorescence, suggesting that PheCN could be used as a local pH sensor.
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49
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Wang YS, Fang X, Chen HY, Wu B, Wang ZU, Hilty C, Liu WR. Genetic incorporation of twelve meta-substituted phenylalanine derivatives using a single pyrrolysyl-tRNA synthetase mutant. ACS Chem Biol 2013; 8:405-15. [PMID: 23138887 DOI: 10.1021/cb300512r] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
When coexpressed with its cognate amber suppressing tRNACUAPyl(CUA), a pyrrolysyltRNA synthetase mutant N346A/C348A is able to genetically incorporate 12 meta-substituted phenylalanine derivatives into proteins site-specifically at amber mutation sites in Escherichia coli. These genetically encoded noncanonical amino acids resemble phenylalanine in size and contain diverse bioorthogonal functional groups such as halide, trifluoromethyl, nitrile, nitro,ketone, alkyne, and azide moieties. The genetic installation of these functional groups in proteins provides multiple ways to site-selectively label proteins with biophysical and biochemical probes for their functional investigations. We demonstrate that a genetically incorporated trifluoromethyl group can be used as a sensitive 19F NMR probe to study protein folding/unfolding, and that genetically incorporated reactive functional groups such as ketone,alkyne, and azide moieties can be applied to site-specifically label proteins with fluorescent probes. This critical discovery allows the synthesis of proteins with diverse bioorthogonal functional groups for a variety of basic studies and biotechnology development using a single recombinant expression system.
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Affiliation(s)
- Yane-Shih Wang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Xinqiang Fang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Hsueh-Ying Chen
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Bo Wu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Zhiyong U. Wang
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Christian Hilty
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Wenshe R. Liu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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50
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Pazos IM, Gai F. Solute's perspective on how trimethylamine oxide, urea, and guanidine hydrochloride affect water's hydrogen bonding ability. J Phys Chem B 2012; 116:12473-8. [PMID: 22998405 PMCID: PMC3475735 DOI: 10.1021/jp307414s] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
While the thermodynamic effects of trimethylamine oxide (TMAO), urea, and guanidine hydrochloride (GdnHCl) on protein stability are well understood, the underlying mechanisms of action are less well characterized and, in some cases, even under debate. Herein, we employ the stretching vibration of two infrared (IR) reporters, i.e., nitrile (C≡N) and carbonyl (C═O), to directly probe how these cosolvents mediate the ability of water to form hydrogen bonds with the solute of interest, e.g., a peptide. Our results show that these three agents, despite having different effects on protein stability, all act to decrease the strength of the hydrogen bonds formed between water and the infrared probe. While the behavior of TMAO appears to be consistent with its protein-protecting ability, those of urea and GdnHCl are inconsistent with their role as protein denaturants. The latter is of particular interest as it provides strong evidence indicating that although urea and GdnHCl can perturb the hydrogen-bonding property of water their protein-denaturing ability does not arise from a simple indirect mechanism.
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Affiliation(s)
- Ileana M. Pazos
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
| | - Feng Gai
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104
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