TY - Generic T1 - Stabilization of Terahertz Vibrational Modes in Illuminated Orange Carotenoid Protein Crystals T2 - 2020 45th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) Y1 - 2020 A1 - McKinney, J. A1 - Sharma, A. A1 - Deng, Y. A1 - George, D. A1 - Lechno-Yossef, S. A1 - Kerfeld, C. A1 - Markelz, A. AB -
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.
JF - 2020 45th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW-THz) CY - Buffalo, NY ER - TY - JOUR T1 - Blue Shift of a Molecular Crystal Phonon at the Solid to Liquid Phase Transition JF - Bulletin of the American Physical Society Y1 - 2019 A1 - Davie, Alex A1 - Vandrevala, Farah A1 - Deng, Yanting A1 - George, D. A1 - Sylvester, Eric D. A1 - Korter, T. A1 - Einarsson, E. A1 - Benedict, Jason B. A1 - Markelz, Andrea VL - 2019 ER - TY - JOUR T1 - The Effect of Crystal Contact Forces on the Protein Global Motions JF - Biophysical Journal Y1 - 2019 A1 - McKinney, J. A. A1 - Deng, Y. T. A1 - George, D. A1 - Markelz, A. KW - Biophysics VL - 116 SN - 0006-3495 N1 - ISI Document Delivery No.: HO2XGWe report a new broad band technique for rapidly measuring the complex Faraday and Kerr rotations in materials such as topological insulators and graphene, combining the distinct advantages of THz time domain spectroscopy and polarization modulation techniques. The performance of the system is demonstrated using GaAs two dimensional electron gas in a magnetic field.
JF - 2011 36th International Conference on Infrared, Millimeter, and Terahertz Waves T3 - International Conference on Infrared Millimeter and Terahertz Waves PB - Ieee CY - New York SN - 978-1-4577-0509-0 N1 - ISI Document Delivery No.: BJT73We demonstrate a new technique for characterizing the phonons in molecular crystals, Modulated Orientation Sensitive Terahertz Spectroscopy (MOSTS). The technique suppresses crystal defects and solvent contributions, and enhances contributions due to molecular structure and anisotropy.
JF - Frontiers in Optics 2010 CY - Rochester ER - TY - Generic T1 - The role of the protein surface on the local biological water dynamics T2 - Biosensing Ii Y1 - 2009 A1 - Liang, W. A1 - He, Y. F. A1 - George, D. A1 - Markelz, A. G. ED - Razeghi, M. ED - Mohseni, H. KW - alanine KW - dynamics KW - hydration KW - lysine KW - lysozyme KW - proteins KW - relaxation KW - spectroscopy KW - Terahertz KW - thz AB -Protein function is reliant on structural flexibility and this flexibility is slaved to the surrounding solvent. Here we discuss how the exposed surface of the protein influences the solvent dynamics and thereby influences the protein's own structural dynamics. We discuss measurements of the THz absorption of water in the presence of hydrophilic and hydrophobic surfaces.
JF - Biosensing Ii T3 - Proceedings of SPIE PB - Spie-Int Soc Optical Engineering CY - Bellingham VL - 7397 SN - 978-0-8194-7687-6 N1 - ISI Document Delivery No.: BVQ85