01967nas a2200349 4500008004500000020001400045245009200059210006900151260000800220300001400228490000700242520094400249653001501193653002101208653002701229653001201256653002701268653002101295653003401316653002301350653003001373653002601403653002201429653001401451100001301465700001401478700001701492700001701509700002001526700002201546856004901568 2008 Engldsh a0006-349500aTerahertz spectroscopy of bacteriorhodopsin and rhodopsin: Similarities and differences0 aTerahertz spectroscopy of bacteriorhodopsin and rhodopsin Simila cApr a3217-32260 v943 a
We studied the low-frequency terahertz spectroscopy of two photoactive protein systems, rhodopsin and bacteriorhodopsin, as a means to characterize collective low-frequency motions in helical transmembrane proteins. From this work, we found that the nature of the vibrational motions activated by terahertz radiation is surprisingly similar between these two structurally similar proteins. Specifically, at the lowest frequencies probed, the cytoplasmic loop regions of the proteins are highly active; and at the higher terahertz frequencies studied, the extracellular loop regions of the protein systems become vibrationally activated. In the case of bacteriorhodopsin, the calculated terahertz spectra are compared with the experimental terahertz signature. This work illustrates the importance of terahertz spectroscopy to identify vibrational degrees of freedom which correlate to known conformational changes in these proteins.
10aBiophysics10abovine rhodopsin10aconformational-changes10aelastic10afrequency normal-modes10alight activation10amolecular-dynamics simulation10aneutron-scattering10aprotein-coupled receptors10atransmembrane helices10avibrational-modes10awild-type1 aBalu, R.1 aZhang, H.1 aZukowski, E.1 aChen, J., Y.1 aMarkelz, A., G.1 aGregurick, S., K. uhttps://markelz.physics.buffalo.edu/node/22201209nas a2200253 4500008004500000020001400045245006500059210006500124260000800189300000600197490000700203520054700210653001300757653001300770653001200783653001700795653001000812100001700822700001700839700001500856700001500871700002000886856004900906 2007 Engldsh a0003-695100aTerahertz dielectric assay of solution phase protein binding0 aTerahertz dielectric assay of solution phase protein binding cJun a30 v903 aThe authors demonstrate a method for rapid determination of protein-ligand binding on solution phase samples using terahertz dielectric spectroscopy. Measurements were performed using terahertz time domain spectroscopy on aqueous solutions below the liquid-solid transition for water. Small ligand binding sensitivity was demonstrated using triacetylglucosamine and hen egg white lysozyme with a decrease in dielectric response with binding. The magnitude of the change increases with frequency. (c) 2007 American Institute of Physics.
10adynamics10alysozyme10aPhysics10aspectroscopy10awater1 aChen, J., Y.1 aKnab, J., R.1 aYe, S., J.1 aHe, Y., F.1 aMarkelz, A., G. uhttps://markelz.physics.buffalo.edu/node/22301575nas a2200337 4500008004500000020001400045245011100059210006900170260000800239300000600247490000700253520062400260653002900884653002200913653001200935653001700947653001400964653002300978653001701001100001801018700001301036700001701049700001701066700002001083700001701103700001701120700001601137700001801153700001701171856004901188 2006 Engldsh a0003-695100aTerahertz transmission characteristics of high-mobility GaAs and InAs two-dimensional-electron-gas systems0 aTerahertz transmission characteristics of highmobility GaAs and cSep a30 v893 aFrequency-dependent complex conductivity of high-mobility GaAs and InAs two-dimensional-electron-gas (2DEG) systems is studied by terahertz time domain spectroscopy. Determining the momentum relaxation time from a Drude model, the authors find a lower value than that from dc measurements, particularly at high frequencies/low temperatures. These deviations are consistent with the ratio tau(t)/tau(q,) where tau(q) is the full scattering time. This suggests that small-angle scattering leads to weaker heating of 2DEGs at low temperatures than expected from dc mobilit9y. (c) 2006 American Institute of Physics.
10afield-effect transistors10aphotoconductivity10aPhysics10aplasma-waves10aradiation10aresonant detection10asubterahertz1 aKabir, N., A.1 aYoon, Y.1 aKnab, J., R.1 aChen, J., Y.1 aMarkelz, A., G.1 aReno, J., L.1 aSadofyev, Y.1 aJohnson, S.1 aZhang, Y., H.1 aBird, J., P. uhttps://markelz.physics.buffalo.edu/node/229