Kinetic, structural and dynamic properties of Pseudomonas haloplanktis 2/2HbO-2217

ALONSO DE ARMIÑO, DIEGO JAVIER; DI LELLA, SANTIAGO; MONTEPIETRA, DANIELE; DELCANALLE, P.; BRUNO, S.; GIORDANO, D.; VERDE, C.; ESTRIN, DARÍO ARIEL; VIAPPIANI, C.; ABBRUZZETTI, S.

Córdoba

Congreso; LI Reunión Anual de la Sociedad Argentina de Biofísica; 2023

Sociedad Argentina de Biofisica

Due to the low temperature, the Antarctic marine environment is challenging for protein functioning. The reduced thermal energy and the increased viscosity of water, for instance, slow down all reaction rates and impact on dynamics and flexibility of proteins.The main challenge for Antarctic organisms is to cope with increased O 2 solubility at low temperatures that significantly increases the production rate of reactive-oxygen species (ROS). Therefore, cold-adapted organisms have developed enhanced antioxidant capacity, resulting from multiple genes that encode catalases and superoxide dismutases.The high reactivity of Ph-2/2HbO-0030 5 and Ph-2/2HbO-2217 7 to peroxynitrite suggests that protection against reactive-nitrogen species (RNS) and ROS is important in the cold. The ferric form of Ph2/2HbO-2217 is able to catalyse peroxynitrite isomerisationin vitro, indicating its potential role in the scavenging of RNS.With the aim to describe kinetic and dynamic properties of Ph 2/2HbO-2217, in this work we combine an experimental and computational approach and present a new computational method to retrieve information from molecular dynamic trajectories inorder to identify docking sites within the protein matrix able to accommodate ligands and migration pathways connecting them. We findthat the analysis of molecular dynamics simulations of small ligand migration through the interior of the protein, provides a compelling explanation of the CO rebinding kinetic constants observed in laser flash photoysis experiments.