A5042859209- Hemoglobin structure and function
- Protein Structure and Dynamics
- Enzyme Structure and Function
- Spectroscopy and Quantum Chemical Studies
- Photoreceptor and optogenetics research
- Mass Spectrometry Techniques and Applications
- Heme Oxygenase-1 and Carbon Monoxide
- Photosynthetic Processes and Mechanisms
- Photochemistry and Electron Transfer Studies
- Electrochemical Analysis and Applications
- Infection Control and Ventilation
- Advanced X-ray Imaging Techniques
- Neonatal Health and Biochemistry
- Spectroscopy and Laser Applications
- Advanced NMR Techniques and Applications
- X-ray Spectroscopy and Fluorescence Analysis
- Spectroscopy Techniques in Biomedical and Chemical Research
- Biochemical effects in animals
- Erythrocyte Function and Pathophysiology
- Neuroscience and Neuropharmacology Research
- Various Chemistry Research Topics
- Crystallography and Radiation Phenomena
- Laser-Matter Interactions and Applications
- Retinal Development and Disorders
- bioluminescence and chemiluminescence research
National Institute of Diabetes and Digestive and Kidney Diseases
2013-2024
National Institutes of Health
2015-2024
University of Chicago
2002-2005
Korea Advanced Institute of Science and Technology
2005
Harvard University
1992-2004
Pusan National University
1999-2004
Harvard–MIT Division of Health Sciences and Technology
2004
Rice University
2003
University of Wisconsin–Madison
2003
European Synchrotron Radiation Facility
2003
Speech droplets generated by asymptomatic carriers of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are increasingly considered to be a likely mode disease transmission. Highly sensitive laser light scattering observations have revealed that loud speech can emit thousands oral fluid per second. In closed, stagnant air environment, they disappear from the window view with time constants in range 8 14 min, which corresponds droplet nuclei ca. 4 μm diameter, or 12- 21-μm prior...
We report picosecond time-resolved x-ray diffraction from the myoglobin (Mb) mutant in which Leu 29 is replaced by Phe (L29Fmutant). The frame-by-frame structural evolution, resolved to 1.8 angstroms, allows one literally “watch” protein as it executes its function. Time-resolved mid-infrared spectroscopy of flash-photolyzed L29F MbCO revealed a short-lived CO intermediate whose 140-ps lifetime shorter than that found wild-type factor 1000. electron density maps unveil transient...
result on serum RT-qPCR assay for yellow fever.Liver-biopsy samples showed lobular necroinflammation, which included many foci of spotty necrosis, apoptosis, and hydropic hepatocyte degeneration in all zones, without typical midzonal lesions associated with fever, along extensive hypercellularity hypertrophy Kupffer cells.Some the patients had confluent necrosis.Among who underwent liver biopsy, immunohistochemical analysis was positive fever antigen, found mainly Kupffer-cell cytoplasm;...
The relative orientations of carbon monoxide (CO) bound to and photodissociated from myoglobin in solution have been determined with time-resolved infrared polarization spectroscopy. CO is oriented < or = 7 degrees the heme normal, corresponding nearly linear FE-C-O. Upon dissociation Fe, becomes trapped a docking site that orientationally constrains it lie approximately plane heme. Because "docked" are orthogonal directions binding suppressed. These solutions results help establish how...
Determining 3D intermediate structures during the biological action of proteins in real time under ambient conditions is essential for understanding how function. Here we use time-resolved Laue crystallography to extract short-lived and thereby unveil signal transduction blue light photoreceptor photoactive yellow protein (PYP) from Halorhodospira halophila. By analyzing a comprehensive set data PYP photocycle (forty-seven points one nanosecond second), track all atoms its directly observe...
Although conformational changes are essential for the function of proteins, little is known about their structural dynamics at atomic level resolution. Myoglobin (Mb) paradigm to investigate because it a simple globular heme protein displaying photosensitivity iron–ligand bond. Upon laser photodissociation carboxymyoglobin Mb nonequilibrium population structures generated that relaxes over broad time range extending from picoseconds milliseconds. This process associated with migration ligand...
The primary events in the all- trans to 13- cis photoisomerization of retinal bacteriorhodopsin have been investigated with femtosecond time-resolved absorbance spectroscopy. Spectra measured over a broad range extending from 7000 22,400 cm −1 reveal features whose dynamics are inconsistent model proposed earlier account for highly efficient process. Emerging this work is new three-state model. Photoexcitation visible light accesses shallow well on excited state potential energy surface....
To understand how signaling proteins function, it is crucial to know the time-ordered sequence of events that lead state. We recently developed on BioCARS 14-IDB beamline at Advanced Photon Source infrastructure required characterize structural changes in protein crystals with near-atomic spatial resolution and 150-ps time resolution, have used this capability track reversible photocycle photoactive yellow (PYP) following trans-to-cis photoisomerization its p-coumaric acid (pCA) chromophore...
The photodissociation of CO from HbCO at ambient temperature is studied by means a femtosecond IR technique. bleaching the FeCO absorption and appearance new near that free are both observed 300 fs after optical excitation. bleach does not recover on time scale few picoseconds but approximately 4% within 1 ns, which suggests barrier to recombination formed picoseconds. spectrum change significantly between suggesting quickly finds some locations in heme pocket more than angstroms iron....
We have developed a time-resolved x-ray scattering diffractometer capable of probing structural dynamics proteins in solution with 100-ps time resolution. This diffractometer, on the ID14B BioCARS (Consortium for Advanced Radiation Sources) beamline at Photon Source, records snapshots over broad range q spanning 0.02-2.5 A(-1), thereby providing simultaneous coverage small-angle (SAXS) and wide-angle (WAXS) regions. To demonstrate its capabilities, we tracked changes myoglobin as it...
A chopper system for time resolved pump-probe experiments with x-ray beams from a synchrotron is described. The has three parts: water-cooled heatload chopper, high-speed and millisecond shutter. system, which installed in beamline ID09B at the European Synchrotron Radiation Facility, provides short pulses ultrafast lasers. can produce as 200 ns continuous beam repeat frequencies 0 to 3 kHz. For bunch filling patterns of pulse separations greater than 100 ns, isolate single ps that are used...
BioCARS, a NIH-supported national user facility for macromolecular time-resolved X-ray crystallography at the Advanced Photon Source (APS), has recently completed commissioning of an upgraded undulator-based beamline optimized single-shot laser-pump X-ray-probe measurements with time resolution as short 100 ps. The source consists two in-line undulators periods 23 and 27 mm that together provide high-flux pink-beam capability 12 keV well first-harmonic coverage from 6.8 to 19 keV. A...
We present a crystallography chip enabling in situ room temperature at microfocus synchrotron beamlines and X-ray free-electron laser (X-FEL) sources.Compared to other approaches, we observe extremely low background high diffraction data quality.The design is robust allows fast efficient loading of thousands small crystals.The ability load large number protein crystals, with efficiency, into prescribed positions enables throughput automated serial beamlines.In addition, demonstrate the...
A joint analysis of all-atom molecular dynamics (MD) calculations and picosecond time-resolved x-ray structures was performed to gain single-molecule insights into mechanisms protein function. Ensemble-averaged MD simulations the L29F mutant myoglobin after ligand dissociation reproduce direction, amplitude, time scales crystallographically determined structural changes. This close agreement with experiments at comparable resolution in space validates individual trajectories. From 1,700...
The picosecond evolution of the tertiary conformation myoglobin (Mb) after photodissociation MbCO was investigated at room temperature by probing band III, a weak iron-porphyrin charge-transfer transition near 13,110 cm-1 (763 nm) that is sensitive to out-of-plane displacement iron. Upon photolysis, iron moves out plane porphyrin, causing blue-shift III and concomitant change in protein conformation. dynamics for this functionally important motion are highly nonexponential, agreement with...
Time-resolved mid-ir absorption spectra of CO at 283 K have been measured 100 ps after photodissociation from human hemoglobin A, horse myoglobin, and sperm whale myoglobin. The reveal two vibrational features that are narrower than any reported for in the condensed phase near room temperature, indicating becomes localized a rotationally constrained environment. integrated absorbance under these narrow is 0.53±0.05 times found myoglobin low temperature glasses. A model developed relates this...
We present a time-resolved x-ray diffraction study to monitor the recombination of laser-dissociated iodine molecules dissolved in ${\mathrm{CCl}}_{4}$. The change structure is followed during whole process. deexcitation solute produces heating solvent and induces tiny changes its structure. variations distance between pairs chlorine atoms adjacent ${\mathrm{CCl}}_{4}$ are probed on $m\AA{}$ length scale. However, most striking outcome work experimental determination temporally varying...
Work carried out over the last 30 years unveiled role of structural dynamics in controlling protein function. Cavity networks modulate trajectories and are functionally relevant; globins they have been assigned a ligand migration docking. These findings raised renewed interest for time-resolved investigations myoglobin (Mb), simple heme displaying photosensitive iron-ligand bond. Photodissociation MbCO generates nonequilibrium population structures relaxing time range extending from...
Significance Development of specialized instrumentation enables rapid switching the hydrostatic pressure inside an operating NMR spectrometer. This technology allows observation protein signals during repeated folding process. Applied to ubiquitin, a previously extensively studied model folding, methodology reveals initially highly dynamic state that deviates relatively little from random coil behavior but also provides evidence for numerous repeatedly failed events, only observed in...