Structural rearrangement in the Xanthomonas campestris bacteriophytochrome during photoconversion (Póster)

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

Valparaíso

Congreso; III Reunión de la Asociación Latinoamericana de Cristalografía; 2018

Asociación Latinoamericana de Cristalografía (LACA)

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 structures of the photosensory module alone (deltaPAS9) in its far red-absorbing state (Pfr) at 2.90 A resolution and the full-length Pfr-stabilized XccBphP G454E mutant at 2.50 A resolution. In this work, we will describe the main properties of the different variants obtained and the biophysical and biochemical aspects that govern the activation and interconversion of the Pr and Pfr forms of the protein. This work provides new insights in the understanding of the molecular mechanisms behind phytochrome signaling in bacteria and its role in infection, and may serve as a model for the orthologous phytochromes present in plants.