00443nas a2200157 4500008004100000245004800041210004000089490000800129100001500137700001900152700001600171700001700187700001600204700001600220856004900236 2020 eng d00aIs the Protein Dynamical Transition useful?0 aProtein Dynamical Transition useful0 v1181 aSharma, A.1 aGeorge, D., K.1 aCrossen, K.1 aMcKinney, J.1 aKerfeld, C.1 aMarkelz, A. uhttps://markelz.physics.buffalo.edu/node/28201881nas a2200181 4500008004100000245009900041210006900140260001600209520131100225100001701536700001501553700001301568700001501581700002201596700001601618700001601634856004901650 2020 eng d00aStabilization of Terahertz Vibrational Modes in Illuminated Orange Carotenoid Protein Crystals0 aStabilization of Terahertz Vibrational Modes in Illuminated Oran aBuffalo, NY3 a
Orange carotenoid protein (OCP) controls efficiency of the phycobilisome (PBS), the light harvesting antenna in cyanobacteria, to prevent oxidative damage. The OCP switches from resting state to photo protective state with intense blue light illumination. Questions persist as to why OCPR interaction increases with the PBS over that with the OCPO. Here we examine the role of long-range intramolecular vibrations within OCP. Using Stationary Sample Anisotropic Terahertz Microscopy (SSATM) we measure changes in the intramolecular vibrations with photo switching. We report the first observation of switching in the intramolecular vibrations with photoexcitation. Results suggest that there is a stiffening of the molecule in the photo protective state. This increase in structural stability may enhance the interaction with the PBS change in OCP interaction with PBS. In low light, carotenoid bound OCP appears orange (OCP o ) and is inactive. Illumination by strong light converts OCP to the active, red (OCPR) state, which interacts with the PBS. A comparison of anisotropic THz microscopy measurements of dark adapted (OCP o ) and illuminated OCP crystals indicate differences in their vibrational modes that may be important for OCP-PBS interactions.
1 aMcKinney, J.1 aSharma, A.1 aDeng, Y.1 aGeorge, D.1 aLechno-Yossef, S.1 aKerfeld, C.1 aMarkelz, A. uhttps://markelz.physics.buffalo.edu/node/54401287nas a2200145 4500008004100000245005300041210005300094260002400147520086300171100001501034700001201049700001501061700001601076856004901092 2020 eng d00aTHz Transmission through Submillimeter Apertures0 aTHz Transmission through Submillimeter Apertures aBuffalo NYc11/20203 aTerahertz near-field microspectroscopy is emerging as an essential tool for characterization of novel materials and biomolecules. It is important to ensure the near field geometry used does not introduce spectral artifacts. For example, many scanning techniques can be strongly influenced by the interaction between the scattering tip and the sample. Here we examine the spectroscopic effects of a 200 μm diameter aperture for THz near-field measurements. We use HFSS to model free-space transmission through samples with resonant absorbance as a function of sample thickness, lateral sample width, and aperture diameter. We examine the transmitted power and spectral fidelity for coupling of transmitted THz light onto a detector. These studies inform corrective post-measurement analysis algorithms and design of near-field detection systems.
1 aLaFave, T.1 aLee, A.1 aKao, T.-Y.1 aMarkelz, A. uhttps://ieeexplore.ieee.org/document/937092300524nas a2200169 4500008004500000020001400045245008200059210006900141260000800210300001400218490000800232653001500240100001700255700001700272700001600289856004900305 2019 Engldsh a0006-349500aDeuteration and Inhibitor Binding Dependence of Protein Collective Vibrations0 aDeuteration and Inhibitor Binding Dependence of Protein Collecti cFeb a488A-488A0 v11610aBiophysics1 aDeng, Y., T.1 aMcKinney, J.1 aMarkelz, A. uhttps://markelz.physics.buffalo.edu/node/24800542nas a2200181 4500008004500000020001400045245007100059210006700130260000800197300001400205490000800219653001500227100002100242700001700263700001500280700001600295856004900311 2019 Engldsh a0006-349500aThe Effect of Crystal Contact Forces on the Protein Global Motions0 aEffect of Crystal Contact Forces on the Protein Global Motions cFeb a489A-489A0 v11610aBiophysics1 aMcKinney, J., A.1 aDeng, Y., T.1 aGeorge, D.1 aMarkelz, A. uhttps://markelz.physics.buffalo.edu/node/25102599nas a2200205 4500008004500000020001400045245005800059210005800117260000800175300001400183490000800197520204200205653001502247100001702262700001702279700001302296700001902309700001602328856004902344 2019 Engldsh a0006-349500aSpectral Assignment of Lysozyme Collective Vibrations0 aSpectral Assignment of Lysozyme Collective Vibrations cFeb a564A-564A0 v1163 aGlobal structural vibrations at terahertz (THz) frequencies have been associated with protein function and allosteric control. A chief obstacle to utilizing this control mechanism has been measurement of specific motions. Recently it was shown that while the vibrational density of states, and isotropic absorption spectra are broad and featureless, collective vibrations can be isolated based on their directionality using aligned samples (realized with protein crystals) and anisotropic THz microscopy [1]. However the assignment of resonant bands to specific structural motions was complicated by the high symmetry of the tetragonal crystals used, and the slow experimental method. To structurally map the vibrations of the chicken egg white lysozyme (CEWL) we measure anisotropic absorption of triclinic crystals using our new technique: ideal polarization varying anisotropic THz microscopy (IPV-ATM). The low symmetry triclinic crystals provide absolute protein orientation, and the near field IPV-ATM rapidly measures broadband terahertz linear dichroism of the microcrystals. All measurements were performed at room temperature under 100% humidity conditions. The unit cell parameters of triclinic lysozyme nitrate crystals, α = 28.5A°, b = 32.7A°, c = 35.1A°, α = 88.2°, β = 108.9°, γ = 111.9°, belonging to the P1 space group, were determined by X-ray diffraction before and after THz measurements. The intramolecular vibrational absorbance of the triclinic crystals has a more complex polarization dependence than the higher symmetry tetragonal crystals, as expected. While the tetragonal crystals have two strong bands at 45cm−1 and 55cm−1, the triclinic crystals have a series of narrow bands between 40 and 60cm−1 and a prominent band at 30cm−1. We compare the measured spectra to normal mode ensemble averaged calculations to assign the observed resonances, and isolating which collective motions impact the catalytic site.
10aBiophysics1 aDeng, Y., T.1 aMcKinney, J.1 aRomo, T.1 aGrossfield, A.1 aMarkelz, A. uhttps://markelz.physics.buffalo.edu/node/24900410nas a2200121 4500008004100000245007200041210006900113490001200182100001300194700001100207700001600218856005400234 2018 eng d00aInvestigation of the Isotope Shift in Protein Collective Vibrations0 aInvestigation of the Isotope Shift in Protein Collective Vibrati0 vA50.0131 aLuck, C.1 aXu, M.1 aMarkelz, A. uhttp://meetings.aps.org/link/BAPS.2018.MAR.A50.1300501nas a2200145 4500008004100000245011200041210006900153490001200222100001100234700001300245700001300258700001500271700001600286856005300302 2018 eng d00aMeasuring Protein Intramolecular Dynamics with Terahertz Light: Functional Changes and Relevance to Biology0 aMeasuring Protein Intramolecular Dynamics with Terahertz Light F0 vH50.0011 aXu, M.1 aDeng, Y.1 aLuck, C.1 aSharma, A.1 aMarkelz, A. uhttp://meetings.aps.org/link/BAPS.2018.MAR.H50.100451nas a2200121 4500008004100000245010900041210006900150490001200219100001300231700001600244700001600260856005300276 2018 eng d00aRapid Terahertz Dichroism Near Field Microscopy for Biomolecular Intramolecular Vibrational Spectroscopy0 aRapid Terahertz Dichroism Near Field Microscopy for Biomolecular0 vA50.0081 aDeng, Y.1 aNiessen, K.1 aMarkelz, A. uhttp://meetings.aps.org/link/BAPS.2018.MAR.A50.800508nas a2200145 4500008004100000245011600041210006900157260001200226100001300238700001100251700001200262700002000274700001600294856005200310 2017 eng d00aGlobal Picosecond Structural Dynamics of Orange Carotenoid Protein in Photo/Chemical Activated Signaling States0 aGlobal Picosecond Structural Dynamics of Orange Carotenoid Prote c03/20171 aDeng, Y.1 aXu, M.1 aLiu, H.1 aBlankenship, R.1 aMarkelz, A. uhttp://meetings.aps.org/link/BAPS.2017.MAR.S4.200406nas a2200121 4500008004100000245006500041210006500106100001100171700001400182700002000196700001600216856005200232 2017 eng d00aTemperature dependence of phonons in photosynthesis proteins0 aTemperature dependence of phonons in photosynthesis proteins1 aXu, M.1 aMyles, D.1 aBlankenship, R.1 aMarkelz, A. uhttp://meetings.aps.org/link/BAPS.2017.MAR.S4.302295nas a2200289 4500008004500000020001400045245010500059210006900164260000800233300001600241490000800257520142900265653001401694653002301708653002401731653001301755653002201768653002201790653002901812653001701841653002001858653002701878653002001905100001501925700001601940856004901956 2010 Engldsh a1520-610600aHydration Effects on Energy Relaxation of Ferric Cytochrome C Films after Soret-Band Photoexcitation0 aHydration Effects on Energy Relaxation of Ferric Cytochrome C Fi cNov a15151-151570 v1143 aProtein hydration plays a critical role in protein dynamics and biological processes. Pump-probe transmission measurement has been applied to investigate the hydration effects on the energy relaxation of a heme protein ferric Cytochrome c (Cyt c) film after soret-band photoexcitation. Transient dynamics study indicates that the energy internal conversion time of similar to 300 fs is independent of hydration. The vibrationally excited electronic ground-state recovery rates show two transitions at the hydration level of h = 12.4-16.5% and 21.7-23.5%. The first transition occurs at the hydration level for the onset of an increasing ferric Cyt c flexibility while the second transition occurs at the saturated hydration level. The hydration dependence of steady-state electronic absorption spectrum results shows that the Q-band peak is nearly constant in center wavelength, but the line width surprisingly narrows with increasing hydration. For the similar to 695 nm absorbance associated with the MET80-Fe bond, the intensity increases with increasing hydration and slightly blue shifts. The 695 nm peak grows rapidly at h = 12.4% and then plateaus at h = 21.7%. This research shows that similar to 695 nm absorbance and ground-state recovery rates are sensitive to the hydration of the protein. This study will aid in understanding how hydration modulates the activity of the protein dynamics at a local level.
10aChemistry10acircular-dichroism10aconformation change10adynamics10aferricytochrome-c10aprotein hydration10aresolved resonance raman10aspectroscopy10aunfolded states10avibrational-relaxation10awater-molecules1 aYe, S., J.1 aMarkelz, A. uhttps://markelz.physics.buffalo.edu/node/27401583nas a2200241 4500008004100000020001400041245006200055210006100117260001100178300001200189490000700201520093300208100002001141700001401161700001901175700001501194700001601209700001601225700001501241700002001256700001601276856004901292 1995 eng d a0167-278900aNONLINEAR QUANTUM DYNAMICS IN SEMICONDUCTOR QUANTUM-WELLS0 aNONLINEAR QUANTUM DYNAMICS IN SEMICONDUCTOR QUANTUMWELLS cMay 15 a229-2420 v833 aWe discuss recent measurements of the nonlinear response of electrons in wide quantum wells driven by intense electromagnetic radiation at terahertz frequencies. The theme is the interplay of quantum mechanics, strong periodic driving, the electron-electron interaction and dissipation. We discuss harmonic generation from an asymmetric double quantum well in which the effects of dynamic screening are important. Measurements and theory are found to be in good agreement. We also discuss intensity-dependent absorption in a 400 Angstrom square quantum well. A new nonlinear quantum effect occurs, in which the frequency at which electromagnetic radiation is absorbed shifts to the red with increasing intensity. The preliminary experimental results are in agreement with a theory by Zaluzny, in which the source of the nonlinearity is the self-consistent potential in the Hartree approximation for the electron dynamics.
1 aSherwin, M., S.1 aCraig, K.1 aGaldrikian, B.1 aHeyman, J.1 aMarkelz, A.1 aCampman, K.1 aFafard, S.1 aHopkins, P., F.1 aGossard, A. uhttps://markelz.physics.buffalo.edu/node/272