Structural characterization of the full-length bacteriophytochrome XccBphP in the Pr and Pfr states (Póster)

SEBASTIÁN KLINKE; JIMENA RINALDI; LISANDRO OTERO; MAXIMILIANO SÁNCHEZ-LAMAS; HERNÁN BONOMI; GIULIANO T. ANTELO; FERNANDO A. GOLDBAUM

Campinas

Encuentro; 29th Annual Users Meeting of the Brazilian Synchrotron Light Laboratory (LNLS); 2019

Brazilian Synchrotron Light Laboratory (LNLS)

Bacteriophytochromes (BphPs) are part of the phytochrome superfamily of photoreceptors. BphPs are proteins that bind biliverdin (BV) as their chromophore and typically present two photostates: a primarily red-absorbing form (Pr) and a far-red-absorbing form (Pfr). The phytopathogenic bacterium Xanthomonas campestris codes for a single bacteriophytochrome photoreceptor (XccBphP) that bears a photosensory module (PAS2-GAF-PHY domains) and a C-terminal PAS9 output module. This microorganism is able to regulate its virulence by sensing red and far-red light through XccBphP. We have crystallized and determined the structure of the dimeric full-length XccBphP in its red-absorbing state (Pr) at 3.25 A resolution. Very recently, we have also solved the crystal structures of the photosensory module alone (delta-PAS9) in its far red-absorbing state (Pfr) at 2.90 A resolution and a full-length Pfr-stabilized XccBphP mutant variant at 2.50 A resolution. These structures significantly help us to acquire a more comprehensive understanding on the long range structural signaling in a full-length bacteriophytochrome at the atomic level.