Bizionia argentinensis copper chaperones

NOELIA I. BURGARDT; GUSTAVO APESTEGUIA; F. LUIS GONZÁLEZ FLECHA

Tucuman

Congreso; XLI Reunion Anual de la Sociedad Argentina de Biofisica; 2012

Sociedad Argentina de Biofisica

<!-- @page { margin: 2cm } P { margin-bottom: 0.21cm } --> Cellular copper homeostasis depends of two key proteins, the CPx-type heavy metal ATPases, which transport copper across cell membranes, and the copper chaperones, which mediate intracellular copper transport.1 Among the copper chaperone proteins there is a group known as CopZ, whose function is to transfer copper to CPx-type heavy metal ATPases. The three-dimensional structure of CopZ proteins from several organisms have been determined.2 The general fold is highly conserved and consists of a twisted four-stranded antiparallel β-sheet and two α-helices which are located on the same side of the β-sheet. The metal binding motif (MXCXXC) is found both in copper binding proteins, such as in proteins that bind another metals. The genome of Bizionia argentinensis (JUB59-T), a psycrophilic bacterium from the Antarctica sea surface, was recently reported.3 The are four open reading frames in B. argentinensis genome with homology to CopZ. Two putative proteins (BaCopZ-33 and BaCopZ-57), which should encoded for small proteins (13.1 and 15.5 kDa, respectively), were selected by our group. Here, we report the cloning, expression and preliminary characterization of BaCopZ-33 and BaCopZ-57. The study of these psychrophilic proteins and its interaction with copper would provide novel data on the mechanism of copper binding at low temperatures and would allow a comparison with the structures and mechanisms of analogous CopZ proteins from mesophilic organisms.