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Peng HC, Mohan S, Huq MT, Bull JA, Michaud T, Piercy TC, Hilber S, Wettasinghe AP, Slinker JD, Kreutz C, Stelling AL. Isotope-Edited Variable Temperature Infrared Spectroscopy for Measuring Transition Temperatures of Single A-T Watson-Crick Base Pairs in DNA Duplexes. Anal Chem 2024; 96:8868-8874. [PMID: 38775341 DOI: 10.1021/acs.analchem.4c00056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024]
Abstract
Experimental methods to determine transition temperatures for individual base pair melting events in DNA duplexes are lacking despite intense interest in these thermodynamic parameters. Here, we determine the dimensions of the thymine (T) C2═O stretching vibration when it is within the DNA duplex via isotopic substitutions at other atomic positions in the structure. First, we determined that this stretching state was localized enough to specific atoms in the molecule to make submolecular scale measurements of local structure and stability in high molecular weight complexes. Next, we develop a new isotope-edited variable temperature infrared method to measure melting transitions at various locations in a DNA structure. As an initial test of this "sub-molecular scale thermometer", we applied our T13C2 difference infrared signal to measure location-dependent melting temperatures (TmL) in a DNA duplex via variable temperature attenuated total reflectance Fourier transform infrared (VT-ATR-FTIR) spectroscopy. We report that the TmL of a single Watson-Crick A-T base pair near the end of an A-T rich sequence (poly T) is ∼34.9 ± 0.7°C. This is slightly lower than the TmL of a single base pair near the middle position of the poly T sequence (TmL ∼35.6±0.2°C). In addition, we also report that the TmL of a single Watson-Crick A-T base pair near the end of a 50% G-C sequence (12-mer) is ∼52.5 ± 0.3°C, which is slightly lower than the global melting Tm of the 12-mer sequence (TmL ∼54.0±0.9°C). Our results provide direct physical evidence for end fraying in DNA sequences with our novel spectroscopic methods.
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Affiliation(s)
- Hao-Che Peng
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Shrijaa Mohan
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Muhammad T Huq
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Julie A Bull
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Troy Michaud
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Turner C Piercy
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Stefan Hilber
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck 6020, Austria
| | - Ashan P Wettasinghe
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Jason D Slinker
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Christoph Kreutz
- Institute of Organic Chemistry and Center for Molecular Biosciences Innsbruck (CMBI), University of Innsbruck, Innsbruck 6020, Austria
| | - Allison L Stelling
- Department of Chemistry and Biochemistry, The University of Texas at Dallas, Richardson, Texas 75080, United States
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2
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Feng RR, Wang M, Zhang W, Gai F. Unnatural Amino Acids for Biological Spectroscopy and Microscopy. Chem Rev 2024; 124:6501-6542. [PMID: 38722769 DOI: 10.1021/acs.chemrev.3c00944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/23/2024]
Abstract
Due to advances in methods for site-specific incorporation of unnatural amino acids (UAAs) into proteins, a large number of UAAs with tailored chemical and/or physical properties have been developed and used in a wide array of biological applications. In particular, UAAs with specific spectroscopic characteristics can be used as external reporters to produce additional signals, hence increasing the information content obtainable in protein spectroscopic and/or imaging measurements. In this Review, we summarize the progress in the past two decades in the development of such UAAs and their applications in biological spectroscopy and microscopy, with a focus on UAAs that can be used as site-specific vibrational, fluorescence, electron paramagnetic resonance (EPR), or nuclear magnetic resonance (NMR) probes. Wherever applicable, we also discuss future directions.
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Affiliation(s)
- Ran-Ran Feng
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Manxi Wang
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Wenkai Zhang
- Department of Physics and Applied Optics Beijing Area Major Laboratory, Beijing Normal University, Beijing 100875, China
| | - Feng Gai
- Beijing National Laboratory for Molecular Sciences, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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3
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Kurttila M, Rumfeldt J, Takala H, Ihalainen JA. The interconnecting hairpin extension "arm": An essential allosteric element of phytochrome activity. Structure 2023; 31:1100-1108.e4. [PMID: 37392739 DOI: 10.1016/j.str.2023.06.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Revised: 05/23/2023] [Accepted: 06/06/2023] [Indexed: 07/03/2023]
Abstract
In red-light sensing phytochromes, isomerization of the bilin chromophore triggers structural and dynamic changes across multiple domains, ultimately leading to control of the output module (OPM) activity. In between, a hairpin structure, "arm", extends from an interconnecting domain to the chromophore region. Here, by removing this protein segment in a bacteriophytochrome from Deinococcus radiodurans (DrBphP), we show that the arm is crucial for signal transduction. Crystallographic, spectroscopic, and biochemical data indicate that this variant maintains the properties of DrBphP in the resting state. Spectroscopic data also reveal that the armless systems maintain the ability to respond to light. However, there is no subsequent regulation of OPM activity without the arms. Thermal denaturation reveals that the arms stabilize the DrBphP structure. Our results underline the importance of the structurally flexible interconnecting hairpin extensions and describe their central role in the allosteric coupling of phytochromes.
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Affiliation(s)
- Moona Kurttila
- University of Jyvaskyla, Nanoscience Center, Department of Biological and Environmental Science, 40014 Jyvaskyla, Finland
| | - Jessica Rumfeldt
- University of Jyvaskyla, Nanoscience Center, Department of Biological and Environmental Science, 40014 Jyvaskyla, Finland
| | - Heikki Takala
- University of Jyvaskyla, Nanoscience Center, Department of Biological and Environmental Science, 40014 Jyvaskyla, Finland.
| | - Janne A Ihalainen
- University of Jyvaskyla, Nanoscience Center, Department of Biological and Environmental Science, 40014 Jyvaskyla, Finland.
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4
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Paul S, Jeništová A, Vosough F, Berntsson E, Mörman C, Jarvet J, Gräslund A, Wärmländer SKTS, Barth A. 13C- and 15N-labeling of amyloid-β and inhibitory peptides to study their interaction via nanoscale infrared spectroscopy. Commun Chem 2023; 6:163. [PMID: 37537303 PMCID: PMC10400569 DOI: 10.1038/s42004-023-00955-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 07/06/2023] [Indexed: 08/05/2023] Open
Abstract
Interactions between molecules are fundamental in biology. They occur also between amyloidogenic peptides or proteins that are associated with different amyloid diseases, which makes it important to study the mutual influence of two polypeptides on each other's properties in mixed samples. However, addressing this research question with imaging techniques faces the challenge to distinguish different polypeptides without adding artificial probes for detection. Here, we show that nanoscale infrared spectroscopy in combination with 13C, 15N-labeling solves this problem. We studied aggregated amyloid-β peptide (Aβ) and its interaction with an inhibitory peptide (NCAM1-PrP) using scattering-type scanning near-field optical microscopy. Although having similar secondary structure, labeled and unlabeled peptides could be distinguished by comparing optical phase images taken at wavenumbers characteristic for either the labeled or the unlabeled peptide. NCAM1-PrP seems to be able to associate with or to dissolve existing Aβ fibrils because pure Aβ fibrils were not detected after mixing.
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Affiliation(s)
- Suman Paul
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
- attocube systems AG, Haar, Germany
| | - Adéla Jeništová
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Faraz Vosough
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Elina Berntsson
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
- Department of Chemistry and Biotechnology, Tallinn University of Technology, Tallinn, Estonia
| | - Cecilia Mörman
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
- Department of Biosciences and Nutrition, Karolinska Institutet, Huddinge, Sweden
| | - Jüri Jarvet
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
- National Institute of Chemical Physics and Biophysics, Tallinn, Estonia
| | - Astrid Gräslund
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | | | - Andreas Barth
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden.
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El Samrout O, Berlier G, Lambert JF, Martra G. Polypeptide Chain Growth Mechanisms and Secondary Structure Formation in Glycine Gas-Phase Deposition on Silica Surfaces. J Phys Chem B 2023; 127:673-684. [PMID: 36637235 PMCID: PMC9884078 DOI: 10.1021/acs.jpcb.2c07382] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Peptide formation by amino acids condensation represents a crucial reaction in the quest of the origins of life as well as in synthetic chemistry. However, it is still poorly understood in terms of efficiency and reaction mechanism. In the present work, peptide formation has been investigated through thermal condensation of gas-phase glycine in fluctuating silica environments as a model of prebiotic environments. In-situ IR spectroscopy measurements under a controlled atmosphere reveal that a humidity fluctuating system subjected to both temperature and water activity variations results in the formation of more abundant peptides compared to a dehydrated system subjected only to temperature fluctuations cycles. A model is proposed in which hydration steps result in the hydrolysis and redistribution of the oligomers formed during previous deposition in dry conditions. This results in the formation of self-assembled aggregates with well-defined secondary structures (especially β-sheets). Upon further monomers feeding, structural elements are conserved in newly growing chains, with indications of templated polymerization. The structural dynamics of peptides were also evaluated. Rigid self-assembled structures with a high resistance to further wetting/drying cycles and inaccessibility to isotopic exchange were present in the humidity fluctuating system compared to more flexible structures in the dehydrated system. The resistance and growth of self-assembled structures were also investigated for an extended duration of Gly deposition using isotope labeling.
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Affiliation(s)
- Ola El Samrout
- Department
of Chemistry and NIS Centre, University
of Torino, Via P. Giuria 7, 10125Torino, Italy,Laboratoire
de Réactivité de Surface, LRS (UMR 7197 CNRS), Sorbonne Université, Place Jussieu, 75005Paris, France
| | - Gloria Berlier
- Department
of Chemistry and NIS Centre, University
of Torino, Via P. Giuria 7, 10125Torino, Italy,
| | - Jean-François Lambert
- Laboratoire
de Réactivité de Surface, LRS (UMR 7197 CNRS), Sorbonne Université, Place Jussieu, 75005Paris, France,
| | - Gianmario Martra
- Department
of Chemistry and NIS Centre, University
of Torino, Via P. Giuria 7, 10125Torino, Italy
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