? Discovering function from protein structure: The BA42 protein from the antarctic bacteria B. Argentinensis is a novel phosphatase.

CLARA SMAL; MARTÍN ARAN; LEONARDO PELLIZZA; MARIANA GALLO; ANDRES BERCOVICH; WALTER P. MAC CORMACK; ADRIAN G. TURJANSKI; DANIEL O. CICERO

Pisa

Congreso; XLI National Meeting of the GIDRM; 2012

GIDRM

The bacteria Bizionia argentinensis sp. Nov (BA) was isolated from surface seawater in Antarctica and the phylogenetic analysis showed that it belongs to a novel species of the genus Bizionia [1]. The BA genome was recently decoded [2] and constitutes a relevant source for the discovery of new proteins showing biological activity in extreme conditions of low temperatures. In particular, we are interested in those proteins for which function cannot be inferred solely on sequence, and for which structural homologues are not available. To study this type of proteins, a network of NMR Laboratories was created, giving birth to the Extremophiles Structural Genomics consortium (ESG). ESG includes the NMR Laboratories of Fundación Instituto Leloir, Buenos Aires, Argentina, Verona University and Parma University, Italy. In this work we present the first structure of a BA protein of unknown function, the BA42 protein, codified by the ORF 00042 contig 3 [3].  BA42 presents significant sequence identity with a PfamA family, DUF477 (Domain of Unknown Function). Proteins of this family are found both in eukarya and eubacteria. The three-dimensional structure consists in a three-layer sandwich with three a-helices in the upper layer, four b-sheets in the middle layer, and one a-helix in the lower layer. Using the DALI server [4], we found three remote structural homologues of BA42. One of these homologues was recently characterized as an acid phosphatase of the thylakoid lumen in plants [5]. We will present the first biochemical evidences showing that BA42 presents phosphatase activity as well, pointing to the discovery of a novel type of phosphatases associated to the DUF477 domain.