期刊
JOURNAL OF MOLECULAR BIOLOGY
卷 413, 期 1, 页码 128-137出版社
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jmb.2011.08.031
关键词
blue-light receptor; flavin; photoreduction; diffusion; conformational dynamics
资金
- Ministry of Education, Science, Sports, and Culture in Japan [18205002, 20107003]
- National Science Foundation [0848311]
- National Institutes of Health [GM37684]
- International Center for Integrated Research and Advanced Education in Material Science, Kyoto University, Japan
- Skaggs Institute for Chemical Biology
- Direct For Biological Sciences
- Div Of Molecular and Cellular Bioscience [0848311] Funding Source: National Science Foundation
Cryptochromes (CRYs) are widespread flavoproteins with homology to photolyases (PHRs), a class of blue-light-activated DNA repair enzymes. Unlike PHRs, both plant and animal CRYs have a C-terminal domain. This cryptochrome C-terminal (CCT) domain mediates interactions with other proteins, while the PHR-like domain converts light energy into a signal via reduction and radical formation of the flavin adenine dinucleotide cofactor. However, the mechanism by which the PHR-like domain regulates the CCT domain is not known. Here, we applied the pulsed-laser-induced transient grating method to detect conformational changes induced by blue-light excitation of full-length Arabidopsis thaliana cryptochrome 1 (AtCRY1). A significant reduction in the diffusion coefficient of AtCRY1 was observed upon photoexcitation, indicating that a large conformational change occurs in this monomeric protein. AtCRY1 containing a single mutation (W324F) that abolishes an intra-protein electron transfer cascade did not exhibit this conformational change. Moreover, the conformational change was much reduced in protein lacking the CCT domain. Thus, we conclude that the observed large conformational changes triggered by light excitation of the PHR-like domain result from C-terminal domain rearrangement. This inter-domain modulation would be critical for CRYs' ability to transduce a blue-light signal into altered protein protein interactions for biological activity. Lastly, we demonstrate that the transient grating technique provides a powerful method for the direct observation and understanding of photoreceptor dynamics. (C) 2011 Elsevier Ltd. All rights reserved.
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