SMC02309, A NOVEL LOW MOLECULAR WEIGHT PHOSPHOTYROSINE PHOSPHATASE FROM Sinorhizobium meliloti

MEDEOT D.; RIVERO M. R.; CENDOYA E.; FERRARI W; ROSSI F.; CONTRERAS-MOREIRA B.; FISCHER S.; JOFRÉ E.

mendoza

Congreso; SAIB Sociedad Argentina de bioquimica y biología molecular 48 th encuentro; 2012

In Gram-negative bacteria tyrosine phosphorylation has been shown to play a role in polysaccharide production. The predicted protein product of open reading frame Smc02309 from possesses significant similarity with known low molecular weight protein tyrosine phosphatases (LMW-PTP).KMandVmaxparametersforSMc02309towardspnitrophenyl phosphate are similar to those of other biochemical characterized bacterial LMW-PTP. Using a combination of immunodetection, mass spectrometric analysis and bioinformatics approaches, it was shown that SMc02309 is a protein phosphatase. Moreover, preliminary results provide evidence that the phosphataseSMc02309canutilizetheproteintyrosinekinaseExoP as an endogenous substrate. Bioinformatics approaches also evidence that, in contrary that happen in other bacterial species, in the genome these both proteins present a unique location.Altogether,theseresultssuggesttheoccurrenceofanovel regulatory mechanism connected with protein phosphorylation on tyrosine in . The identification and functional characterizationofthisnovelphosphotyrosine-proteinphosphatase will increase our understanding of key aspects of polysaccharides biosynthesis not only in bacteria of agricultural significance but also in polysaccharides-producing proteobacteria with human and animalhealthrelevance.