STRUCTURAL CHARACTERIZATION OF THE FULL-LENGTH BACTERIOPHYTOCHROME XccBphP IN THE PR AND PFR STATES

KLINKE, S.; RINALDI, J.; ANTELO, G.T.; GOLBAUM, F.A.; OTERO, L.H.; SÁNCHEZ-LAMAS, M.; BONOMI, H.R.

Campinas

Congreso; 29th Reunión Anual de Usuarios del Sincrotrón LNLS/CNPEM Campinas 2019; 2019

LNLS/CNPEM

Bacteriophytochromes (BphPs) are part of the phytochrome superfamily of photoreceptors. BphPs are proteins that bind biliverd in (BV) as their chromophoreand typically present two photostates: a primarily red-absorbing form (Pr) and a far-red-absorbing form (Pfr) [1]. The phytopathogenic bacteriumXanthomonas campestris codes for a single bacteriophytochrome photoreceptor (XccBphP) that bears a photosensory module (PAS2-GAF-PHY domains) and aC-terminal PAS9 output module. This microorganism is able to regulate its virulence by sensing red and far-red light through XccBphP [2].We havecrystallized [3] and determined the structure of the dimeric full-length XccBphP in its red-absorbing state (Pr) at 3.25 Å resolution [4]. Very recently, we havealso solved the crystal structures of the photosensory module alone (ΔPAS9) in its far red-absorbing state (Pfr) at 2.90 Å resolution and a full-length PfrstabilizedXccBphP mutant variant at 2.50 Å resolution. These structures significantly help us to acquire a more comprehensive understanding on the longrangestructural signaling in a full-length bacteriophytochrome at the atomic level.