00524nas 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/24802250nas a2200157 4500008004100000245009400041210006900135260001700204520170800221100001801929700001701947700002701964700002001991700002402011856005702035 2016 eng d00aDirect Measurements of the Long-Range Collective Vibrations of Photoactive Yellow Protein0 aDirect Measurements of the LongRange Collective Vibrations of Ph aBaltimore MD3 a
Long-range collective vibrations are thought to be crucial to protein functions. In the case of photoactive protein family, modeling suggests the intramolecular vibrations provide an efficient means of energy relaxation[1], feedback for enhancement of chromophore vibrations that promote structural transitions[2] and can assist in charge energy transfer[3]. As a paradigm of this family, photoactive yellow protein (PYP) is a cytoplasmic photocycling protein related to negative phototactic response to blue light in purple photosynthetic bacteria. PYP has a p-coumaric acid chromophore binding to the cysteine residue via a thioester bond, whose vibrations were found to overlap calculated vibrations of the protein scaffold. Using our unique technique of anisotropic terahertz microscopy(ATM)[4], we measure the intramolecular vibrations for PYP for the first time, including cycling between ground and blue shift (pB) states. Room temperature ATM measurements are performed in the dark and with continuous wave illumination at 488nm, resulting in a steady pB state with approximately 5% population conversion. In pB state, we find an overall decrease in the strength of resonant band in frequency range of 30-60 cm-1. Our calculated spectra using quasi-harmonic analysis indicate that our measurements are dominated by the protein vibrations, rather than the pCA chromophore, allowing us to characterize how the scaffold dynamics changes with functional states and mutations.
1. Levantino, M., et al. Nat Commun, 2015. 6.
2. Mataga, N., et al. Chem. Phys. Lett., 2002. 352(3-4): p. 220-225.
3. Fokas, A.S., et al. Photosynth. Res., 2014. 122
1 aDeng, Yanting1 aXu, Mengyang1 aNiessen, Katherine, A.1 aSchmidt, Marius1 aMarkelz, Andrea, G. uhttps://onlinelibrary.wiley.com/doi/10.1002/pro.302600593nas a2200169 4500008004100000245007800041210006900119260004100188300001200229490005800241100002000299700001600319700001700335700001100352700001100363856004900374 2007 eng d00aDevelopment of Tagless Biosensors for Detecting the Presence of Pathogens0 aDevelopment of Tagless Biosensors for Detecting the Presence of aDordrecht, The NetherlandsbSpringer a123-1340 ved X.-C. Zhang, R. E. Miles, H. Eisele and A. Krotkus1 aMarkelz, A., G.1 aChen, J.-Y.1 aKnab, J., R.1 aHe, Y.1 aYe, S. uhttps://markelz.physics.buffalo.edu/node/30301306nas a2200325 4500008004100000020001400041245006500055210006500120260001600185300001400201490000700215520044400222653001900666653001600685653001900701653001200720653002300732653001400755100001500769700001500784700001300799700001200812700001100824700001300835700001700848700001200865700001400877700001700891856007200908 2003 eng d a1386-947700aDirect measurements of optical phonons in SrTiO3 nanosystems0 aDirect measurements of optical phonons in SrTiO3 nanosystems c2003/07/01/ a236 - 2390 v193 aWe use terahertz time domain spectroscopy to examine finite size effects on the optical phonon modes in SrTiO3 thin films. In temperature-dependent measurements we find a near absence of mode softening in the TO1 phonon frequency. Furthermore we see an increase in the soft mode frequency with reduced thickness. Both of these results correlate well with the reduced dielectric response observed for nanoscale ferroelectric systems.
10aFerroelectrics10aFinite size10aMode softening10aphonons10aStrontium titanate10aTerahertz1 aWolpert, D1 aKorolev, K1 aSachs, S1 aKnab, J1 aCox, W1 aCerne, J1 aMarkelz, A.G1 aZhao, T1 aRamesh, R1 aMoeckly, B.H uhttps://www.sciencedirect.com/science/article/pii/S138694770300305901474nas a2200193 4500008004100000020001400041245010700055210006900162260001200231300001200243490000700255520087300262100001801135700002001153700001801173700002001191700002001211856004901231 1994 eng d a0038-110100aDC TRANSPORT IN INTENSE, INPLANE TERAHERTZ ELECTRIC-FIELDS IN AL(X)GA(1-X)AS HETEROSTRUCTURES AT 300-K0 aDC TRANSPORT IN INTENSE INPLANE TERAHERTZ ELECTRICFIELDS IN ALXG cApr-Jun a693-6950 v373 aWe report 300 K studies of the dependence of the in-plane, d.c. conductivity, sigma(d.c.) (E(omega)), of a quasi 2D electron gas on the amplitude E(omega) and frequency of intense, far-infrared fields (omega/2pi = 0.24-3.5 THz). We measure sigma(d.c.) (E(omega) parallel-to E(d.c.)), where E(d.c.) is a small sensing field, and observe a monotonic decrease in sigma(d.c.) with increasing E(omega). Although a simple scaling ansatz collapses the measured sigma(d.c.) (E(omega)) data onto a single curve for frequencies from 0.25-3.45 THz (at low to moderate scaled fields), the decrease in conductivity is substantially more rapid than expected from comparison to similar data taken by Masselink et al. [Solid-St. Electron. 31, 337 (1988)] at 35 GHz. We tentatively attribute this difference to effects of a high-frequency modulation in the electron temperature.
1 aAsmar, N., G.1 aMarkelz, A., G.1 aGwinn, E., G.1 aHopkins, P., F.1 aGossard, A., C. uhttps://markelz.physics.buffalo.edu/node/260