Long-range signaling mechanism of Xanthomonas campestris bacteriophytochrome: a dance under red light (Conferencia Plenaria)

LISANDRO H. OTERO; SABRINA FOSCALDI; GIULIANO T. ANTELO; GERMÁN L. ROSANO; SERENA SIRIGU; SEBASTIÁN KLINKE; LUCAS A. DEFELIPE; MAXIMILIANO SÁNCHEZ-LAMAS; GIOVANNI BATTOCCHIO; VALERIA CONFORTE; ADRIAN A. VOJNOV; LEONARD CHAVAS; FERNANDO A. GOLDBAUM; MARÍA A. MROGINSKI; JIMENA RINALDI; HERNÁN R. BONOMI

Córdoba

Congreso; XVII Reunión Anual de la Asociación Argentina de Cristalografía (AACr); 2022

Asociación Argentina de Cristalografía (AACr)

Phytochromes are photo-sensing proteins distributed among plants, fungi and prokaryotes, including pathogens, which reversibly photoconverted, between a red-absorbing (Pr) and a far-red-absorbing (Pfr) state. Despite the vast structural information currently reported, their dynamic protein structures are an extremely challenging matter in structural photobiology where several key questions still remain to be answered. Undoubtedly, one of the most relevant interrogates is how the long-range structural changes are propagated from the light-sensing module (Photosensory Module) to the effector module (Output Module) during the Pr-Pfr photoconversion. This question remains elusive essentially due to two causes: i) overwhelmingly, most reported phytochrome structures are truncated versions, without a complete Output Module, ii) no full-length phytochrome structures have been solved at the atomic level in both pure Pr and Pfr photostates. Our group has reported a complete structural characterization at the atomic level of the bacteriophytochrome from the phytopathogenic Xanthomonas campestris (including two full-length versions) in the Pr and Pfr states. The structures show a reorganization of the interaction networks within and around the chromophore-binding pocket and specific domain reorientations as a result of the photo switching, which subsequently affect the quaternary assembly. These structural findings, combined with multidisciplinary studies, allow us to describe the signaling mechanism of a full-length bacterial phytochrome at the atomic level. In this talk, the light-driven conformational changes during the reversible photo switching in a full-length phytochrome will be exposed.