Possible role of the network of interactions in the cold adaptation of the Cu+transporter ATPase of from Bizionia argentinensis

F LUIS GONZÁLEZ FLECHA; NOELIA I. BURGARDT; NOELIA MELIAN

virtual

Congreso; Congreso virtual de la Sociedad Argentina de Biofisica; 2020

Sociedad Argentina de Biofisica

Modulation of protein stability is key to the adaptation of organisms totheir environment. It is postulated that the type and quantity of non-covalentinteractions between residues plays an important role in the adaptation ofproteins to extreme environments [1]. In our laboratory we study therelationship between stability, structure and function of Cu +transporter PIB-1-ATPases (CopA), whose function is essential for intracellular copperhomeostasis. The structure of CopA consists of four characteristic domains: theheavy metal-associated domain, the catalytic domain, the actuator domain, andthe transmembrane region [2]. The structure of a CopA of themesophilic bacterium Legionellapneumophila (LpCopA) was resolved a few years ago [3]. Thisstructure served as a template to obtain a model of the Cu +transporter ATPase of the psychrotolerant bacterium Bizionia argentinensis (BaCopA). Both proteins show high homology(51.8%) and identity (80.8%) in sequence. BaCopA has fewer ionic interactionsthan LpCopA and these are mainly found in the soluble domains. On the otherhand, BaCopA presents a greater number of p-p interactions locatedmainly in the transmembrane regions. Ionic interactions are mostly conserved inthe catalytic domain of both proteins, mainly those located in the P subdomain,where the formation and hydrolysis of the phosphorylated intermediate takesplace. On the contrary, they are poorly conserved in the actuator domain and itis in this domain where there is the greatest difference between the twoproteins. These particularities could confer a greater structural flexibilityto BaCopA compared to LpCopA, which would account for its ability to adapt tolow temperatures