scholarly journals Amyloid-Like Structures Formed by Azobenzene Peptides: Light-Triggered Disassembly

2012 ◽  
Vol 27 ◽  
pp. 387-391 ◽  
Author(s):  
Andreas A. Deeg ◽  
Tobias E. Schrader ◽  
Halina Strzalka ◽  
Jose Pfizer ◽  
Luis Moroder ◽  
...  
Keyword(s):  
Amino Acid ◽  
Ir Spectroscopy ◽  
Time Scale ◽  
Optical Excitation ◽  
Excess Energy ◽  
Structural Rearrangements ◽  
Time Resolved ◽  
Spectral Signatures ◽  
Disassembly Process ◽  
Azobenzene Chromophore

The light-driven disassembly process of amyloid-like structures formed by azobenzene model peptides is studied by time-resolved mid-IR spectroscopy from nanoseconds to minutes. The investigated peptide consists of two amino acid strands connected by the azobenzene switch. The peptides aggregate to amyloid-like structures when the azobenzene chromophore is in thetrans-conformation. Illumination, resulting in atrans-tocis-isomerization of the azobenzene, leads to disaggregation of the aggregated structures. After optical excitation and isomerization of the azobenzene, one finds absorption changes which recover to a large extent on the time scale of few nanoseconds. These early absorption transients are assigned to the relaxation of vibrational excess energy (heat) or to structural rearrangements of isomerized azobenzene and the aggregated surroundings. It is only on the time scale of minutes that spectral signatures appear which are characteristic for the disassembly of the aggregated structure.

scholarly journals Single water solvation dynamics in the 4-aminobenzonitrile–water cluster cation revealed by picosecond time-resolved infrared spectroscopy

2015 ◽  
Vol 17 (44) ◽  
pp. 29969-29977 ◽  
Author(s):  
Mitsuhiko Miyazaki ◽  
Takashi Nakamura ◽  
Matthias Wohlgemuth ◽  
Roland Mitrić ◽  
Otto Dopfer ◽  
...  
Keyword(s):  
Infrared Spectroscopy ◽  
Time Scale ◽  
Water Cluster ◽  
Local Minimum ◽  
Excess Energy ◽  
Solvation Dynamics ◽  
Time Resolved ◽  
Water Solvent ◽  
Cluster Cation ◽  
Time Resolved Infrared Spectroscopy

The excess energy of photoionization can control the time scale of single water solvent orientation dynamics from picoseconds to infinitely long trapping in a local minimum.

Surface chemistry of H-ZSM5 studied by time-resolved IR spectroscopy

1989 ◽  
Vol 51 (3) ◽  
pp. 309-327 ◽  
Author(s):  
Andreas Jentys ◽  
Gerhard Warecka ◽  
Johannes A. Lercher
Keyword(s):  
Ir Spectroscopy ◽  
Surface Chemistry ◽  
Time Resolved

Time-resolved FTIR study of CO recombination with horseradish peroxidase

2008 ◽  
Vol 36 (6) ◽  
pp. 1165-1168 ◽  
Author(s):  
Amandine Maréchal ◽  
W. John Ingledew ◽  
Peter R. Rich
Keyword(s):  
Fourier Transform ◽  
Ir Spectroscopy ◽  
Horseradish Peroxidase ◽  
Rate Constants ◽  
Recombination Rate ◽  
Thermal Equilibrium ◽  
Time Resolved ◽  
Fourier Transform Ir Spectroscopy ◽  
Rapid Scan ◽  
Fourier Transform Ir

Vibrational changes associated with CO recombination to ferrous horseradish peroxidase were investigated by rapid-scan FTIR (Fourier-transform IR) spectroscopy in the 1200–2200 cm−1 range. At pH 6.0, two conformers of bound CO are present that appear as negative bands at 1905 and 1934 cm−1 in photolysis spectra. Their recombination rate constants are identical, confirming that they arise from two substates of bound CO that are in rapid thermal equilibrium, rather than from heterogeneous protein sites. A smaller positive band at 2134 cm−1 also appears on photolysis and decays with the same rate constant, indicative of an intraprotein geminate site involved in recombination or, possibly, a weak-affinity surface CO-binding site. Other signals arising from protein and haem in the 1700–1200 cm−1 range can also be time-resolved with similar kinetics.

Time-resolved IR spectroscopy reveals mechanistic details of ion transport in the sodium pump Krokinobacter eikastus rhodopsin 2

2019 ◽  
Vol 21 (8) ◽  
pp. 4461-4471 ◽  
Author(s):  
Marvin Asido ◽  
Peter Eberhardt ◽  
Clara Nassrin Kriebel ◽  
Markus Braun ◽  
Clemens Glaubitz ◽  
...  
Keyword(s):  
Ir Spectroscopy ◽  
Comparative Study ◽  
Ion Transport ◽  
Structural Dynamics ◽  
Sodium Pump ◽  
Proton Pumping ◽  
Wild Type ◽  
Time Resolved

We report a comparative study on the structural dynamics of the light-driven sodium pump Krokinobacter eikastus rhodopsin 2 wild type under sodium and proton pumping conditions by means of time-resolved IR spectroscopy.

scholarly journals Visualizing a viral genome with contrast variation small angle X-ray scattering

2020 ◽  
Vol 295 (47) ◽  
pp. 15923-15932
Author(s):  
Josue San Emeterio ◽  
Lois Pollack
Keyword(s):  
Small Angle ◽  
Viral Genome ◽  
Viral Assembly ◽  
Measured Signal ◽  
Structural Rearrangements ◽  
Contrast Variation ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

Despite the threat to human health posed by some single-stranded RNA viruses, little is understood about their assembly. The goal of this work is to introduce a new tool for watching an RNA genome direct its own packaging and encapsidation by proteins. Contrast variation small-angle X-ray scattering (CV-SAXS) is a powerful tool with the potential to monitor the changing structure of a viral RNA through this assembly process. The proteins, though present, do not contribute to the measured signal. As a first step in assessing the feasibility of viral genome studies, the structure of encapsidated MS2 RNA was exclusively detected with CV-SAXS and compared with a structure derived from asymmetric cryo-EM reconstructions. Additional comparisons with free RNA highlight the significant structural rearrangements induced by capsid proteins and invite the application of time-resolved CV-SAXS to reveal interactions that result in efficient viral assembly.

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