Many bacterial pathogens inject into host cells effector proteins that are substrates for host tyrosine kinases such as Src and Abl family kinases. Phosphorylated effectors eventually subvert host cell signaling, aiding disease development. In the case of the gastric pathogen Helicobacter pylori, which is a major risk factor for the development of gastric cancer, the only known effector protein injected into host cells is the oncoprotein CagA. Here, we followed the hierarchic tyrosine phosphorylation of H. pylori

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Several polyene macrolides are potent antifungal agents that have severe side effects. Increased glycosylation of these compounds can improve water-solubility and reduce toxicity. Three extending glycosyltransferases are known to add hexoses to the mycosaminyl sugar residues of polyenes. The adds an extra hexose to a nystatin but the identity of the sugar is unknown. Here we express the nypY gene in Streptomyces nodosus amphL and show that NypY modifies 8-deoxyamphotericins more efficiently than C-8 hydroxylated forms. The modified heptaene was purified and shown to be mannosyl-8-deoxyamphotericin B. Actinoplanes caeruleusThis had the same antifungal activity as amphotericin B, but was slightly less haemolytic. Chemical modification of this new disaccharide polyene could give better antifungal antibiotics.