TY - JOUR T1 - Evidence of Intramolecular Structural Stabilization in Light Activated State of Orange Carotenoid Protein JF - Biophysical Journal Y1 - 2020 A1 - McKinney, J. A. A1 - Sharma, A. A1 - Crossen, K. A1 - Deng, Y. A1 - George, D. K. A1 - Lechno-Yossef, S. A1 - Kerfeld, C. A1 - Markelz, A. G. KW - Biophysics AB -

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 12Å 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.

VL - 118 SN - 0006-3495 IS - 3 N1 - 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.

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Cell press
Cambridge
1542-0086 ER -