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[摘要]：Aureochrome1, a signaling photoreceptor from a eukaryotic photosynthetic stramenopile, confers blue-light-regulated DNA binding on the organism. Its topology, in which a C-terminal LOV sensor domain is linked to an N-terminal DNA-binding bZIP effector domain, contrasts with the reverse sensor-effector topology in most other known LOV-photoreceptors. How, then, is signal transmitted in Aureochrome1 ? The dark- and light-state crystal structures of Aureochrome1 LOV domain (AuLOV) show that its helical N- and C-terminal flanking regions are packed against the external surface of the core beta sheet, opposite to the FMN chromophore on the internal surface. Light-induced conformational changes occur in the quaternary structure of the AuLOV dimer and in Phe298 of the H beta strand in the core. The properties of AuLOV extend the applicability of LOV domains as versatile design modules that permit fusion to effector domains via either the N- or C-termini to confer blue-light sensitivity. |
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