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Structure of the photolyase-like domain of cryptochrome 1 from Arabidopsis thaliana

2004; National Academy of Sciences; Volume: 101; Issue: 33 Linguagem: Inglês

10.1073/pnas.0404851101

1091-6490

Chad A. Brautigam, Barbara Smith, Z. Ma, Maya Palnitkar, D.R. Tomchick, Mischa Machius, J. Deisenhofer,

Photosynthetic Processes and Mechanisms

Signals generated by cryptochrome (CRY) blue-light photoreceptors are responsible for a variety of developmental and circadian responses in plants. The CRYs are also identified as circadian blue-light photoreceptors in Drosophila and components of the mammalian circadian clock. These flavoproteins all have an N-terminal domain that is similar to photolyase, and most have an additional C-terminal domain of variable length. We present here the crystal structure of the photolyase-like domain of CRY-1 from Arabidopsis thaliana . The structure reveals a fold that is very similar to photolyase, with a single molecule of FAD noncovalently bound to the protein. The surface features of the protein and the dissimilarity of a surface cavity to that of photolyase account for its lack of DNA-repair activity. Previous in vitro experiments established that the photolyase-like domain of CRY-1 can bind Mg·ATP, and we observe a single molecule of an ATP analog bound in the aforementioned surface cavity, near the bound FAD cofactor. The structure has implications for the signaling mechanism of CRY blue-light photoreceptors.