@conference {441, title = {Anisotropic Terahertz Microscopy of Lysozyme in Different CrystalLattice Systems}, booktitle = {Biophysical Journal}, year = {2021}, month = {02/2021}, abstract = {
Long-range vibrational modes of proteins at terahertz (THz) frequencies havebeen associated with protein function and allosteric control. The characteriza-tion of these motions has been challenging due to energy overlap with waterabsorption and a large vibrational density of states. Recently it has been demon-strated both experimentally and theoretically that vibrational bands can be iso-lated using stationary sample anisotropic terahertz microscopy (SSTAM) fororiented samples, typically realized using protein crystals [1, 2]. In those earlymeasurements, inhibitor binding contrast was demonstrated for high symmetrytetragonal crystals. While high symmetry crystals are ideal for structural deter-minations, they can limit the types of vibrations observable in the ATM mea-surements. Here we show a survey of ATM measurements of triclinic,monoclinic and tetragonal crystals, demonstrating the unique signaturesobservable for the different symmetry groups, leading to a more completedetermination of the vibrational hot spots that may contribute to enzymatic ef-ficiency. The SSATM spectra indicate the presence of conserved vibrationalmodes near 40 cm-1 and 55 cm-1 for CEWL in triclinic, monoclinic and tetrag-onal lattice systems respectively. For CEWL in the monoclinic lattice system, aprominent band at 20cm1was consistently observed in the SSATM spectrabut not in the triclinic or tetragonal systems. The conserved bands may repre-sent vibrational modes that are unperturbed by crystal contact forces while thedifferences may be related to unique molecular orientation in different crystalsystems.
1.Niessen, K., Y. Deng, and A.G. Markelz,Near-field THz micropo-larimetry.Opt Express, 2019.27(20): p. 28036-28047.
2.Romo, T.D., A.Grossfield, and A.G. MarkelzPersistent Protein Motions in a RuggedEnergy Landscape Revealed by Normal Mode Ensemble Analysis. AcceptedJournal of Chemical Information and Modeling, 2020.
}, doi = {10.1016/j.bpj.2020.11.972}, url = {https://www.cell.com/biophysj/fulltext/S0006-3495(20)31879-8}, author = {McKinney, J. A. and George, D. K. and Deng, Y. and Markelz, A. G.} } @article {329, title = {Near-Field Stationary Sample Terahertz Spectroscopic Polarimetry for Biomolecular Structural Dynamics Determination}, journal = {ACS Photonics}, volume = {8}, year = {2021}, month = {02/2021}, pages = {658-668}, chapter = {658}, abstract = {THz polarimetry on environmentally sensitive and microscopic samples can provide unique insight into underlying mechanisms of complex phenomena. For example, near-field THz anisotropic absorption successfully isolated protein structural vibrations which are connected to biological function. However, to determine how these vibrations impact function requires high throughput measurements of these complex systems, which is challenged by the need for near field detection, sample environmental control and full polarization variation. Stationary sample anisotropic terahertz spectroscopy (SSATS) and near-field stationary sample anisotropic terahertz microscopy (SSATM) have been proposed using synchronous control of THz and electro optic probe polarizations along an iso-response curve. Here we realize these techniques through robust control and calibration of the THz and NIR polarization states. Both methods rapidly measure the linear dichroism in the far field and near field. Validation measurements using standard birefringent sucrose single crystals found the crystal orientation can be determined by scanning the reference polarization and the synchronous pump{\textendash}probe polarization settings can be optimized to eliminate artifacts. SSATM is then used to determine spectral reproducibility and dehydration effects for a series of chicken egg white lysozyme samples. Reproducible anisotropic absorbance bands are found at about 30, 44, 55, and 62 cm{\textendash}1. These bands initially sharpen with slow dehydration, similar to the increase in resolution achieved in X-ray crystallographic protein structure determination. The SSATM technique confirms the reliability of anisotropic absorption characterization of protein intramolecular vibrations and opens an avenue for rapid determination of how these long-range dynamics affect biological function.
}, doi = {10.1021/acsphotonics.0c01876}, url = {https://pubs.acs.org/doi/abs/10.1021/acsphotonics.0c01876}, author = {Deng, Y. and McKinney, J. A. and George, D. K. and Niessen, K. A. and Sharma, A. and Markelz, A.G.} } @article {253, title = {Evidence of Intramolecular Structural Stabilization in Light Activated State of Orange Carotenoid Protein}, journal = {Biophysical Journal}, volume = {118}, number = {3}, year = {2020}, note = {ISI Document Delivery No.: KK8YXOrange carotenoid protein (OCP) controls efficiency of the light harvesting antenna, the phycobilisome (PBS), in diverse cyanobacteria and prevents oxidative damage. It is the only known photoactive protein that uses a carotenoid, canthaxanthin, as its chromophore. The structure of OCP consists of two globular domains, connected by an unstructured loop, that forms a hydrophobic pocket for the carotenoid. In low light, canthaxanthin bound OCP is inactive and appears orange. Illumination by strong light results in an active state that interacts with the PBS to induce fluorescence quenching, a red appearance and conformational changes that include a 12{\r A} shift by canthaxanthin into the N-terminal domain. Terahertz (THz) dynamical transition measurements and anisotropic terahertz microscopy are used to measure the intramolecular structural dynamics in the inactive and active states, which can be induced by photoexcitation or chaotropic salts. The measurements indicate that the active state has a decrease in structural flexibility, which may be related to enhanced interactions with the PBS.
}, keywords = {Biophysics}, isbn = {0006-3495}, doi = {10.1016/j.bpj.2019.11.1245}, author = {McKinney, J. A. and Sharma, A. and Crossen, K. and Deng, Y. and George, D. K. and Lechno-Yossef, S. and Kerfeld, C. and Markelz, A. G.} } @proceedings {544, title = {Stabilization of Terahertz Vibrational Modes in Illuminated Orange Carotenoid Protein Crystals}, year = {2020}, address = {Buffalo, NY}, abstract = {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.
}, doi = {10.1109/IRMMW-THz46771.2020.9370827}, author = {McKinney, J. and Sharma, A. and Deng, Y. and George, D. and Lechno-Yossef, S. and Kerfeld, C. and Markelz, A.} } @conference {306, title = {Protein Intramolecular Motions with Deuteration and Inhibitor Binding Dependence}, booktitle = {APS R63.003}, year = {2019}, month = {03/2019}, url = {https://meetings.aps.org/Meeting/MAR19/Session/R63.3}, author = {Deng, Y. and McKinney, J. and Romo, T. and Grossfield, A. and Markelz, A. G.} } @conference {284, title = {Measuring Protein Intramolecular Dynamics with Terahertz Light: Functional Changes and Relevance to Biology}, booktitle = {APS 2018}, volume = {H50.001}, year = {2018}, url = {http://meetings.aps.org/link/BAPS.2018.MAR.H50.1}, author = {Xu, M. and Deng, Y. and Luck, C. and Sharma, A. and Markelz, A.} } @conference {285, title = {Rapid Terahertz Dichroism Near Field Microscopy for Biomolecular Intramolecular Vibrational Spectroscopy}, booktitle = {APS 2018}, volume = {A50.008}, year = {2018}, url = {http://meetings.aps.org/link/BAPS.2018.MAR.A50.8}, author = {Deng, Y. and Niessen, K. and Markelz, A.} } @conference {288, title = {Global Picosecond Structural Dynamics of Orange Carotenoid Protein in Photo/Chemical Activated Signaling States}, booktitle = {APS 2017 S4.002}, year = {2017}, month = {03/2017}, url = {http://meetings.aps.org/link/BAPS.2017.MAR.S4.2}, author = {Deng, Y. and Xu, M. and Liu, H. and Blankenship, R. and Markelz, A.} }