@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.: KK8YX
Times Cited: 0
Cited Reference Count: 0
McKinney, Jeffrey A. Sharma, Akansha Crossen, Kimberly Deng, Yanting George, Deepu K. Lechno-Yossef, Sigal Kerfeld, Cheryl Markelz, Andrea G.
64th Annual Meeting of the Biophysical-Society
Feb 15-19, 2020
San Diego, CA
Biophys Soc
NSFNational Science Foundation (NSF) [DBI 1556359, MCB 1616529]; DOEUnited States Department of Energy (DOE) [DE-SC0016317]; NIH STTRUnited States Department of Health \& Human ServicesNational Institutes of Health (NIH) - USA [R41 GM125486]
This work is supported by NSF grants DBI 1556359 and MCB 1616529, DOE grant DE-SC0016317 and NIH STTR R41 GM125486.
1
2
Cell press
Cambridge
1542-0086},
month = {Feb},
pages = {208A-208A},
type = {Meeting Abstract},
abstract = {
Orange 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.} } @article {251, title = {The Effect of Crystal Contact Forces on the Protein Global Motions}, journal = {Biophysical Journal}, volume = {116}, number = {3}, year = {2019}, note = {ISI Document Delivery No.: HO2XGWe report 4.2 K studies of the dependence of the in-plane, DC conductivity of a quasi 2D electron gas on the amplitude E(omega) of applied fields with frequencies from 0.25 THz to 3.5 THz. We analyse the dependence of sigma(DC) on E(omega) assuming that electron-optical phonon scattering dominates energy relaxation, that the absorbed power has a Drude form and that the electron distribution is thermal. This simple analysis is self-consistent: Arrhenius plots of the estimated energy loss rate have a slope near -homega(LO)BAR/k(B) for all frequencies, as expected for energy loss by optical phonon emission. We find that the effective energy relaxation time tau(epsilon) varies with the frequency of the applied field, from tau(epsilon) approximately 4 ps at 0.34 THz to tau(epsilon) approximately 0.3 ps at 3.45 THz. This may indicate a frequency-dependent form for the hot-phonon distribution.
}, isbn = {0268-1242}, doi = {10.1088/0268-1242/9/5S/116}, author = {Asmar, N. G. and Markelz, A. G. and Gwinn, E. G. and Hopkins, P. F. and Gossard, A. C.} }