Answer Happy

9.38 The Salmonella toxin Spvc catalytically removes one of the phosphates from the activation loop of MAP kinases (for example FMTPEYPVA) to produce an inactive MAP kinase. The modified kinase cannot be phosphorylated by any MAP kinase kinase. On the basis of mass spectrometry (which detects the neutral forms of phosphate esters), the Spvc catalyzed dephosphorylation leads to a loss of 98 Da, Instead of the 80 Da difference expected for hydrolysis. Suggest a plausible structure for the modification Induced by Spvc. o-P-OH 0-2-0 O ОН O=P Spvc > IZ wy O= zar IZ ! O= N O 0- MAPK activation loop NH EN EL LE ER F