scholarly journals Relationship between protein structural fluctuations and rebinding dynamics in ferric haem nitrosyls

2011 ◽  
Vol 433 (3) ◽  
pp. 459-468 ◽  
Author(s):  
Neil T. Hunt ◽  
Gregory M. Greetham ◽  
Michael Towrie ◽  
Anthony W. Parker ◽  
Nicholas P. Tucker
Keyword(s):  
Vibrational Dynamics ◽  
Time Resolved ◽  
Pump Probe ◽  
2D Ir ◽  
Ligand Rebinding ◽  
Protein Pockets ◽  
Biological Functionality ◽  
The Relationship ◽  
Kinetics Of ◽  
Haem Proteins

The interaction of nitric oxide (NO) with haem proteins is widespread in biology. In the current paper, we present the first ultrafast 2D-IR (two-dimensional infrared) spectroscopic analysis of haem nitrosylation, which has been combined with time-resolved IR pump–probe studies to investigate the relationship between equilibrium vibrational dynamics of the haem environment and ligand rebinding behaviour following photolysis of NO from the Fe(III)–NO site. Studies of two haem proteins, Mb (myoglobin) and Cc (cytochrome c), which play different physiological roles, reveal marked contrasts in the ultrafast fluctuations of the protein pockets containing the haem, showing that the Mb pocket is somewhat more flexible than that of Cc. This correlates strongly with slower observed photolysis rebinding kinetics of Mb–NO compared with Cc–NO, and indicates a direct link between ultrafast fluctuations and biological functionality. Furthermore, this indicates the validity of linear response theories in relation to protein ligand binding. Finally, 2D-IR shows that Cc–NO displays two distinct structural sub-sites at room temperature that do not exchange on the timescales accessible via the NO vibrational lifetime.

scholarly journals Ultrafast dynamics of hydrated excess protons in CH3CN:H2O mixtures

2019 ◽  
Vol 205 ◽  
pp. 09003
Author(s):  
Fabian Dahms ◽  
Achintya Kundu ◽  
Ehud Pines ◽  
Benjamin P. Fingerhut ◽  
Erik T. J. Nibbering ◽  
...  
Keyword(s):  
Ultrafast Dynamics ◽  
Vibrational Dynamics ◽  
Pump Probe ◽  
2D Ir ◽  
Proton Potential ◽  
Hydrated Proton

In a combined experimental and theoretical 2D-IR and pump-probe study we determine how ultrafast solvent motions govern the vibrational dynamics of the hydrated proton and the key role played by the underlying proton potential.

scholarly journals Effect of Dehydrated Trehalose Matrix on the Kinetics of Forward Electron Transfer Reactions in Photosystem I

2017 ◽  
Vol 231 (2) ◽  
Author(s):  
Ivan Shelaev ◽  
Michael Gorka ◽  
Anton Savitsky ◽  
Vasily Kurashov ◽  
Mahir Mamedov ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photosystem I ◽  
Time Domain ◽  
Probe Laser ◽  
Glassy Matrix ◽  
Back Reaction ◽  
Time Resolved ◽  
Pump Probe ◽  
Kinetics Of ◽  
Subnanosecond Time

AbstractThe effect of dehydration on the kinetics of forward electron transfer (ET) has been studied in cyanobacterial photosystem I (PS I) complexes in a trehalose glassy matrix by time-resolved optical and EPR spectroscopies in the 100 fs to 1 ms time domain. The kinetics of the flash-induced absorption changes in the subnanosecond time domain due to primary and secondary charge separation steps were monitored by pump–probe laser spectroscopy with 20-fs low-energy pump pulses centered at 720 nm. The back-reaction kinetics of P

Photoconversion of Spiropyran to Merocyanine in a Monolayer Observed Using Nanosecond Pump-Probe Brewster Angle Reflectometry

2012 ◽  
Vol 65 (3) ◽  
pp. 283 ◽  
Author(s):  
Bernhard Siebenhofer ◽  
Sergey Gorelik ◽  
Anton V. Sadovoy ◽  
Martin J. Lear ◽  
Hong Yan Song ◽  
...  
Keyword(s):  
Conformational Changes ◽  
Brewster Angle ◽  
Time Resolved ◽  
Pump Probe ◽  
Second Stage ◽  
Pump And Probe ◽  
New Apparatus ◽  
Two Stages ◽  
Kinetics Of ◽  
Uv Excitation

A new apparatus for nanosecond-time-resolved Brewster angle reflectometry is described that can be used to measure transient angle-resolved reflectivity changes in thin films and monolayers in a single pulsed laser shot. In order to achieve this, a cylindrical lens is placed in the probe beam path replacing the goniometer that is usually used for angular scanning in other systems. Using two synchronized nanosecond pulsed lasers in pump-probe configuration it is possible to measure the kinetics of photoinduced conformational changes by altering the delay between pump and probe pulses. The system was used to observe nanosecond time-resolved photodynamics in a spiropyran monolayer at the air-water interface. After UV excitation the spiropyran converted to its merocyanine form in two stages. The first stage occurred with a timescale close to the instrument time resolution (tens of nanoseconds) whereas the second stage occurred over a few hundred nanoseconds.

Pump-Probe Measurements Using Silicon Nanocrystal Waveguides

2003 ◽  
Vol 770 ◽  
Author(s):  
Nathanael Smith ◽  
Max J. Lederer ◽  
Marek Samoc ◽  
Barry Luther-Davies ◽  
Robert G. Elliman
Keyword(s):  
Probe Beam ◽  
Time Resolution ◽  
Pump Beam ◽  
Silicon Nanocrystals ◽  
Continuous Wave ◽  
Optical Gain ◽  
Optical Pump ◽  
Time Resolved ◽  
Pump Probe ◽  
Probe Measurements

AbstractOptical pump-probe measurements were performed on planar slab waveguides containing silicon nanocrystals in an attempt to measure optical gain from photo-excited silicon nanocrystals. Two experiments were performed, one with a continuous-wave probe beam and a pulsed pump beam, giving a time resolution of approximately 25 ns, and the other with a pulsed pump and probe beam, giving a time resolution of approximately 10 ps. In both cases the intensity of the probe beam was found to be attenuated by the pump beam, with the attenuation increasing monotonically with increasing pump power. Time-resolved measurements using the first experimental arrangement showed that the probe signal recovered its initial intensity on a time scale of 45-70 μs, a value comparable to the exciton lifetime in Si nanocrystals. These data are shown to be consistent with an induced absorption process such as confined carrier absorption. No evidence for optical gain was observed.

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

Temperature Dependent Kinetics of the OH/HO2/O3Chain Reaction by Time-Resolved IR Laser Absorption Spectroscopy

2000 ◽  
Vol 104 (17) ◽  
pp. 3964-3973 ◽  
Author(s):  
Sergey A. Nizkorodov ◽  
Warren W. Harper ◽  
Bradley W. Blackmon ◽  
David J. Nesbitt
Keyword(s):  
Absorption Spectroscopy ◽  
Laser Absorption Spectroscopy ◽  
Temperature Dependent ◽  
Time Resolved ◽  
Laser Absorption ◽  
Ir Laser ◽  
Kinetics Of

scholarly journals KD determination from time-resolved experiments on live cells with LigandTracer and reconciliation with end-point flow cytometry measurements

2021 ◽  
Author(s):  
Diana Spiegelberg ◽  
Jonas Stenberg ◽  
Pascale Richalet ◽  
Marc Vanhove
Keyword(s):  
Flow Cytometry ◽  
Live Cells ◽  
Time Resolved ◽  
Surface Receptors ◽  
Full Characterization ◽  
End Point ◽  
Titration Curves ◽  
Kinetics Of

AbstractDesign of next-generation therapeutics comes with new challenges and emulates technology and methods to meet them. Characterizing the binding of either natural ligands or therapeutic proteins to cell-surface receptors, for which relevant recombinant versions may not exist, represents one of these challenges. Here we report the characterization of the interaction of five different antibody therapeutics (Trastuzumab, Rituximab, Panitumumab, Pertuzumab, and Cetuximab) with their cognate target receptors using LigandTracer. The method offers the advantage of being performed on live cells, alleviating the need for a recombinant source of the receptor. Furthermore, time-resolved measurements, in addition to allowing the determination of the affinity of the studied drug to its target, give access to the binding kinetics thereby providing a full characterization of the system. In this study, we also compared time-resolved LigandTracer data with end-point KD determination from flow cytometry experiments and hypothesize that discrepancies between these two approaches, when they exist, generally come from flow cytometry titration curves being acquired prior to full equilibration of the system. Our data, however, show that knowledge of the kinetics of the interaction allows to reconcile the data obtained by flow cytometry and LigandTracer and demonstrate the complementarity of these two methods.

Investigation on nonlinear dynamics of ZnO using time-resolved pump-probe technique with phase object

2011 ◽  
Author(s):  
Lirong Ge ◽  
Min Shui ◽  
Xiao Jin ◽  
Zhongguo Li ◽  
Yinglin Song
Keyword(s):  
Nonlinear Dynamics ◽  
Phase Object ◽  
Time Resolved ◽  
Pump Probe ◽  
Probe Technique
Sign in / Sign up

Export Citation Format

Share Document