Structural basis for the Pr-Pfr long-range signaling mechanism of a full-length bacterial phytochrome at the atomic level

OTERO, LISANDRO H. *; FOSCALDI, SABRINA; ANTELO, GIULIANO T.; ROSANO, GERMAN L.; SIRIGU, SERENA; KLINKE, SEBASTIÁN; DEFELIPE, LUCAS A.; SANCHEZ, MAXIMILIANO; BATTOCCHIO, ‌GIOVANNI‌; CONFORTE, VALERIA; VOJNOV, ADRIAN; CHAVAS, LEONARDO; GOLDBAUM, FERNANDO A.; MROGINSKI, MARÍA ANDREA; RINALDI, JIMENA *; BONOMI, HERNAN R.* (* CORRESPONDING AUTHORS)

Science Advances

American Association for the Advancement of Science

Lugar: Washington, D.C.; Año: 2021 vol. 7 p. 1 - 22

2375-2548

Light sensing allowsorganisms to adapt to constantly changing environmental factors.Phytochromes constitute a widespread biological photoreceptor familythat typically interconvert between two photostates called Pr (redlight-absorbing) and Pfr (far-red light-absorbing). Despite the vaststructural information reported on phytochromes, the lack offull-length structures at the (near-)atomic level in both pure Pr andPfr states leaves gaps in the structural mechanisms involved in thesignal transmission pathways during the photoconversion. Here wepresent three crystallographic structures from the plant pathogenXanthomonas campestris virulence regulator bacteriophytochrome,including two full-length proteins, in the Pr and Pfr states. Thestructural findings, combined with mutational, biochemical andcomputational studies, allow us to describe the signaling mechanismof a full-length bacterial phytochrome at the atomic level, from theisomerization of the chromophore and the β-sheet/α-helix tonguetransition to the remodeling of the quaternary assembly of theprotein.p { margin-bottom: 0.25cm; line-height: 115% }