00552nas a2200181 4500008004100000020001400041245006300055210006300118260001000181300001400191490000800205100002700213700001700240700001800257700002200275700002400297856004900321 2017 eng d a0006-349500aImportance of Protein Vibration Directionality on Function0 aImportance of Protein Vibration Directionality on Function cFeb 3 a353A-353A0 v1121 aNiessen, Katherine, A.1 aXu, Mengyang1 aDeng, Yanting1 aSnell, Edward, H.1 aMarkelz, Andrea, G. uhttps://markelz.physics.buffalo.edu/node/25402250nas 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.302601240nas a2200169 4500008004100000020001400041245006600055210006600121300001400187490000800201520070900209100002400918700002100942700002000963700001500983856007200998 2007 eng d a0009-261400aProtein dynamical transition in terahertz dielectric response0 aProtein dynamical transition in terahertz dielectric response a413 - 4170 v4423 a

The 200K protein dynamical transition is observed for the first time in the terahertz dielectric response. The complex dielectric permittivity ε=ε′+iε″ is determined in the 0.2–2.0THz and 80–294K ranges. ε″ has a linear temperature dependence up to 200K then sharply increases. The low temperature linear dependence in ε″ suggests anharmonicity for temperatures 80K<t<180k, challenging="" the="" assumed="" harmonicity="" below="" 200k.="" temperature="" dependence="" is="" consistent="" with="" thermally="" activated="" sidechain="" motions="" and="" shows="" involved="" in="" dynamical="" transition="" extend="" to="" subpicosecond="" time="" scales.<="" div="">

1 aMarkelz, Andrea, G.1 aKnab, Joseph, R.1 aChen, Jing, Yin1 aHe, Yunfen uhttps://www.sciencedirect.com/science/article/pii/S000926140700680X