CrDSP, a PHOSPHOGLUCAN PHOSPHATASE PROBABLY INVOLVED IN STARCH METABOLISM IN C. reinharditii

MORALES, L. L.; CARRILLO, J. B.; GOMEZ-CASATI, D. F.; BUSI, M. V.; MARTÍN, M.

Congreso; LII Reunión Anual Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2016

Phosphatases are enzymes that remove phosphate groups from a wide variety of substrates that includes proteins, glucans, nucleic acids and lipids. It has recently become clear that dephosphorylation of glucans is essential for normal starch degradation in plants as well as glycogen metabolism in mammals. To understand the evolution of catalysis and regulation of these enzymes we decided to investigate their existence in unicellular green algae. C. reinharditii transcriptome BLAST searches revealed one locus encoding a protein with high sequence similarity to A. thaliana starch excess 4 enzyme. An exhaustive in silico analysis led us to conclude that the putative protein could be a chloroplastic enzyme with similar structural features to its plant counterpart. To further characterize this finding the cDNA was cloned to express and purify the recombinant protein in E. coli cells. We verified phosphatase activity of the recombinant enzyme in vitro as well as its ability to bind polysaccharides.